untitled

124 690 07 Rev. L KohlerEngines.com

CV17-CV25, CV620-CV730, CV740, CV750

Service Manual

2 Safety

3 Maintenance

5 Speciﬁ cations

16 Tools and Aids

19 Troubleshooting

23 Air Cleaner/Intake

24 Fuel System

30 Governor System

31 Lubrication System

33 Electrical System

49 Starter System

58 Disassembly/Inspection and Service

75 Reassembly

IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating

instruction of equipment that this engine powers.

Ensure engine is stopped and level before performing any maintenance or service.

SAFETY PRECAUTIONS

WARNING: A hazard that could result in death, serious injury, or substantial property damage.

CAUTION: A hazard that could result in minor personal injury or property damage.

NOTE: is used to notify people of important installation, operation, or maintenance information.

WARNING

Explosive Fuel can cause

ﬁ res and severe burns.

Do not ﬁ ll fuel tank while

engine is hot or running.

Gasoline is extremely ﬂ ammable

and its vapors can explode if

ignited. Store gasoline only in

approved containers, in well

ventilated, unoccupied buildings,

away from sparks or ﬂ ames.

Spilled fuel could ignite if it comes

in contact with hot parts or sparks

from ignition. Never use gasoline

as a cleaning agent.

WARNING

Rotating Parts can cause

severe injury.

Stay away while engine is

in operation.

Keep hands, feet, hair, and

clothing away from all moving

parts to prevent injury. Never

operate engine with covers,

shrouds, or guards removed.

WARNING

Carbon Monoxide can

cause severe nausea,

fainting or death.

Avoid inhaling exhaust

fumes. Never run engine

indoors or in enclosed

spaces.

Engine exhaust gases contain

poisonous carbon monoxide.

Carbon monoxide is odorless,

colorless, and can cause death if

inhaled.

WARNING

Accidental Starts can

cause severe injury or

death.

Disconnect and ground

spark plug lead(s) before

servicing.

Before working on engine or

equipment, disable engine as

follows: 1) Disconnect spark plug

lead(s). 2) Disconnect negative (–)

battery cable from battery.

WARNING

Hot Parts can cause

severe burns.

Do not touch engine while

operating or just after

stopping.

Never operate engine with heat

shields or guards removed.

WARNING

Cleaning Solvents can

cause severe injury or

death.

Use only in well ventilated

areas away from ignition

sources.

Carburetor cleaners and solvents

are extremely ﬂ ammable. Follow

cleaner manufacturer’s warnings

and instructions on its proper and

safe use. Never use gasoline as a

cleaning agent.

CAUTION

Electrical Shock can

cause injury.

Do not touch wires while

engine is running.

CAUTION

Damaging Crankshaft

and Flywheel can cause

personal injury.

Using improper procedures can

lead to broken fragments. Broken

fragments could be thrown from

engine. Always observe and use

precautions and procedures when

installing ﬂ ywheel.

WARNING

Uncoiling Spring can

cause severe injury.

Wear safety goggles or

face protection when

servicing retractable

starter.

Retractable starters contain a

powerful, recoil spring that is

under tension. Always wear safety

goggles when servicing retractable

starters and carefully follow

instructions in Retractable Starter

for relieving spring tension.

2 24 690 07 Rev. LKohlerEngines.com

Safety

MAINTENANCE INSTRUCTIONS

WARNING

Before working on engine or equipment, disable engine as

follows: 1) Disconnect spark plug lead(s). 2) Disconnect

negative (–) battery cable from battery.

Accidental Starts can cause severe injury or

death.

Disconnect and ground spark plug lead(s)

before servicing.

Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair

establishment or individual; however, warranty repairs must be performed by a Kohler authorized dealer.

MAINTENANCE SCHEDULE

Weekly

● Check heavy-duty air cleaner element. Air Cleaner/Intake

Every 25 Hours or Annually¹

● Service/replace low-proﬁ le precleaner. Air Cleaner/Intake

Every 100 Hours or Annually¹

● Replace low-proﬁ le air cleaner element. Air Cleaner/Intake

● Change oil. Lubrication System

● Remove cooling shrouds and clean cooling areas. Air Cleaner/Intake

● Check oil cooler ﬁ ns, clean as necessary (if equipped). Lubrication System

Every 200 Hours

● Change oil ﬁ lter. Lubrication System

● Replace fuel ﬁ lter.

Every 250 Hours¹

● Replace heavy-duty air cleaner element and check inner element. Air Cleaner/Intake

Every 300 Hours³

● Change oil and ﬁ lter (KOHLER PRO 10W-50 oil and KOHLER PRO ﬁ lter only). Lubrication System

Every 500 Hours¹

● Replace heavy-duty inner air cleaner element. Air Cleaner/Intake

● Replace spark plugs and set gap. Electrical System

Every 500 Hours²

● Have crankshaft spline lubricated.

¹ Perform these procedures more frequently under severe, dusty, dirty conditions.

² Have a Kohler authorized dealer perform this service.

³ Option only if using KOHLER

PRO oil and PRO ﬁ lter.

REPAIRS/SERVICE PARTS

Kohler genuine service parts can be purchased from Kohler authorized dealers. To ﬁ nd a local Kohler authorized

dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada).

324 690 07 Rev. L KohlerEngines.com

Maintenance

OIL RECOMMENDATIONS

All-season KOHLER

PRO 10W-50 Synthetic Oil is the

ideal oil for KOHLER engines. It is speciﬁ cally formulated

to extend the oil and oil ﬁ lter change interval to 300

Hours when paired with a KOHLER PRO Extended Life

Oil Filter.

300-Hour oil and oil ﬁ lter change intervals are exclusive

to and only authorized on KOHLER engines that utilize

both the KOHLER PRO 10W-50 Synthetic Oil and

KOHLER PRO Extended Life Oil Filter. Alternative

engine oils and oil ﬁ lters may be used with KOHLER

engines but require 100-Hour oil and 200-Hour oil ﬁ lter

change intervals for proper maintenance. Oil must be

API (American Petroleum Institute) service class SJ or

higher. Select viscosity based on air temperature at time

of operation as shown below.

°F

-20

020324060

50 80 100

°C

-30 -20

-10 0

10 20 30

5W-30

10W-30

SAE 30

Kohler PRO 10W-50

FUEL RECOMMENDATIONS

WARNING

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings,

away from sparks or ﬂ ames. Spilled fuel could ignite

if it comes in contact with hot parts or sparks from

ignition. Never use gasoline as a cleaning agent.

NOTE: E15, E20 and E85 are NOT approved and

should NOT be used; eﬀ ects of old, stale or

contaminated fuel are not warrantable.

Fuel must meet these requirements:

● Clean, fresh, unleaded gasoline.

● Octane rating of 87 (R+M)/2 or higher.

● Research Octane Number (RON) 90 octane minimum.

● Gasoline up to 10% ethyl alcohol, 90% unleaded is

acceptable.

● Methyl Tertiary Butyl Ether (MTBE) and unleaded

gasoline blend (max 15% MTBE by volume) are

approved.

● Do not add oil to gasoline.

● Do not overﬁ ll fuel tank.

● Do not use gasoline older than 30 days.

STORAGE

If engine will be out of service for 2 months or more

follow procedure below.

1. Add Kohler PRO Series fuel treatment or equivalent

to fuel tank. Run engine 2-3 minutes to get stabilized

fuel into fuel system (failures due to untreated fuel

are not warrantable).

2. Change oil while engine is still warm from operation

(NOT required if using KOHLER PRO 10W-50

full-synthetic oil).. Remove spark plug(s) and pour

about 1 oz. of engine oil into cylinder(s). Replace

spark plug(s) and crank engine slowly to distribute

oil.

3. Disconnect negative (-) battery cable.

4. Store engine in a clean, dry place.

4 24 690 07 Rev. LKohlerEngines.com

Maintenance

Dimensions in millimeters.

Inch equivalents shown in [ ].

Engine Dimensions with Low-Proﬁ le Air Cleaner

Speciﬁ cations

524 690 07 Rev. L KohlerEngines.com

Dimensions in millimeters.

Inch equivalents shown in [ ].

Engine Dimensions with Commercial Mower Air Cleaner

Speciﬁ cations

6 24 690 07 Rev. LKohlerEngines.com

Dimensions in millimeters.

Inch equivalents shown in [ ].

Engine Dimensions with Heavy-Duty Air Cleaner

93.30

[3.673]

EXHAUST

PORT #1

73.30

[2.886]

EXHAUST

PORT #2

OIL DRAIN PLUG

3/8 NPT (INCH)

40.80

[1.606]

ENGINE MOUNTING

SURFACE

14.20

[.559]

317.77

[12.511]

377.59

[14.866]

155.30

[6.114]

SPARK PLUG

424.75

[16.722]

89.94

[3.541]

134.97

[5.314]

15.76

[.621]

495.31

[19.501]

45.59

[1.795]

126.31

[4.973]

OIL FILL &

DIPSTICK

MOUNTING

HOLE “A”

15.75

[.620]

OIL FILTER

REMOVAL

301.77

[11.881]

130.03

[5.119]

AIR FILTER COVER

ASSEMBLY REMOVAL

SAFTY AIR FILTER

ELEMENT REMOVAL

PRIMARY AIR FILTER

ELEMENT REMOVAL

AIR FILTER RAIN

CAP REMOVAL

SPARK PLUG

FUEL

FILTER

275.56

[10.849]

15.80

[.622]

SPARK PLUG

417.59

[16.441]

529.91

[20.863]

CRANKSHAFT

89.41

[3.520]

241.66

[9.514]

77.68

[3.058]

334.19

[13.157]

50.00

[1.969]

EXHAUST

PORT #1

2X 89.41

[3.520]

2X 72.85

[2.868]

M8 X 1.25

4 STUDS

SOLENOID

SHIFT STARTER

MOUNTING HOLE “A”

4X Ø 9.20 [.362] THRU

Ø 254.00 [10.00] B.C.

104.02

[4.095]

50.00

[1.969]

EXHAUST

PORT #2

30˚

405.97

[15.983]

247.90

[9.760]

REGULATOR

RECTIFIER

135.30

[5.327]

SPARK

PLUG

52.76

[2.077]

OIL FILTER

14.44

[.569]

96.37

[3.794]

MOUNTING

HOLE “A”

26.41

[1.040]

405.97

[15.983]

OIL DRAIN PLUG

3/8 NPT (INCH)

85.50

[3.366]

KEYWAY

7/16-20 UNF 2B (INCH)

38.1 [1.500]

1/4 IN. SQ KEYWAY

Ø 28.56

[1.125]

ENGINE MOUNTING

SURFACE

449.63

[17.702]

PULSE FUEL

PUMP

OIL COOLER

Speciﬁ cations

724 690 07 Rev. L KohlerEngines.com

GENERAL SPECIFICATIONS

4,7

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Bore 73 mm

(2.87 in.)

77 mm

(3.03 in.)

80 mm

(3.15 in.)

83 mm (3.27 in.)

Stroke 67 mm (2.64 in.) 69 mm

(2.7 in.)

Displacement 561 cc

(34 cu. in.)

624 cc

(38 cu. in.)

674 cc

(41 cu. in.)

725 cc

(44 cu. in.)

747 cc

(46 cu. in.)

Oil Capacity (reﬁ ll) 1.6-1.8 L (1.7-1.9 U.S. qt.)

ENGINE IDENTIFICATION NUMBERS

Kohler engine identiﬁ cation numbers (model, speciﬁ cation and serial) should be referenced for eﬃ cient repair,

ordering correct parts, and engine replacement.

Model . . . . . . . . . . . . . . . . . . . . . CV620

Command Engine

Vertical Shaft

Numerical Designation

Speciﬁ cation . . . . . . . . . . . . . . . CV620-0001

Serial . . . . . . . . . . . . . . . . . . . . . 4923500328

Year Manufactured Code Factory Code

Code Year

49 2019

50 2020

51 2021

Maximum Angle of Operation (@ full oil level)

25°

TORQUE SPECIFICATIONS

4,6

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Blower Housing and Sheet Metal

M5 Fasteners 6.2 N·m (55 in. lb.) into new holes

4.0 N·m (35 in. lb.) into used holes

M6 Fasteners 10.7 N·m (95 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Carburetor and Intake Manifold

Intake Manifold Mounting Fastener (torque in

2 increments)

ﬁ rst to 7.4 N·m (66 in. lb.)

ﬁ nally to 9.9 N·m (88 in. lb.)

Carburetor Mounting Nut 6.2-7.3 N·m (55-65 in. lb.)

Connecting Rod

Cap Fastener (torque in increments)

8 mm straight shank

8 mm step-down

6 mm straight shank

22.7 N·m (200 in. lb.)

14.7 N·m (130 in. lb.)

11.3 N·m (100 in. lb.)

Values are in Metric units. Values in parentheses are English equivalents.

Exceeding maximum angle of operation may cause engine damage from insuﬃ cient lubrication.

Lubricate threads with engine oil prior to assembly.

Any and all horsepower (hp) references by Kohler are Certiﬁ ed Power Ratings and per SAE J1940 & J1995 hp

standards. Details on Certiﬁ ed Power Ratings can be found at KohlerEngines.com.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Speciﬁ cations

8 24 690 07 Rev. LKohlerEngines.com

TORQUE SPECIFICATIONS

4,6

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Crankcase

Breather Cover Fastener 11.3 N·m (100 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Oil Drain Plug 13.6 N·m (10 ft. lb.)

Cylinder Head

Head Fastener

Nut (torque in 2 increments) ﬁ rst to 16.9 N·m (150 in. lb.)

ﬁ nally to 35.5 N·m (315 in. lb.)

Bolt (torque in 2 increments) ﬁ rst to 22.6 N·m (200 in. lb.)

ﬁ nally to 41.8 N·m (370 in. lb.)

Rocker Arm Screw

Black Screw (M6x1.0x34)

Silver Screw (M6x1.0x45)

18.1 N·m (160 in. lb.)

13.6 N·m (120 in. lb.)

Flywheel

Fan Fastener 9.9 N·m (88 in. lb.)

Flywheel Retaining Screw 66.4 N·m (49 ft. lb.)

Fuel Pump

Fastener 2.3 N·m (20 in. lb.)

Governor

Lever Nut 6.8 N·m (60 in. lb.)

Ignition

Spark Plug 27 N·m (20 ft. lb.)

Module Fastener 4.0-6.2 N·m (35-55 in. lb.)

Rectiﬁ er-Regulator Fastener 1.4 N·m (12.6 in. lb.)

Muﬄ er

Retaining Nuts 24.4 N·m (216 in. lb.)

Oil Cooler

Adapter Nipple 27 N·m (20 ft. lb.)

Oil Sentry

™

Pressure Switch 4.5 N·m (40 in. lb.)

Oil Pan

Fastener 24.4 N·m (216 in. lb.)

Solenoid (Starter)

Mounting Hardware

Nippondenso Starter

Delco-Remy Starter

6.0-9.0 N·m (53-79 in. lb.)

4.0-6.0 N·m (35-53 in. lb.)

Nut, Positive (+) Brush Lead

Nippondenso Starter

Delco-Remy Starter

8.0-12.0 N·m (71-106 in. lb.)

8.0-11.0 N·m (71-97 in. lb.)

Values are in Metric units. Values in parentheses are English equivalents.

Lubricate threads with engine oil prior to assembly.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Speciﬁ cations

924 690 07 Rev. L KohlerEngines.com

TORQUE SPECIFICATIONS

4,6

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Speed Control Bracket

Fastener 10.7 N·m (95 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Starter Assembly

Thru Bolt

Inertia Drive

Nippondenso Solenoid Shift

Delco-Remy Solenoid Shift

4.5-5.7 N·m (40-50 in. lb.)

4.5-7.5 N·m (40-84 in. lb.)

5.6-9.0 N·m (49-79 in. lb.)

Mounting Screw 15.3 N·m (135 in. lb.)

Brush Holder Mounting Screw Delco-Remy 2.5-3.3 N·m (22-29 in. lb.)

Stator

Mounting Screw 6.2 N·m (55 in. lb.)

Valve Cover

Gasket Style Cover Fastener 3.4 N·m (30 in. lb.)

Black O-ring Style Cover

With shoulder screws

With ﬂ ange screws and spacers

5.6 N·m (50 in. lb.)

9.9 N·m (88 in. lb.)

Yellow or Brown O-ring Style Cover

With integral metal spacers 9.0 N·m (80 in. lb.)

CLEARANCE SPECIFICATIONS

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Camshaft

End Play (with shim) 0.076/0.127 mm (0.0030/0.0050 in.)

Running Clearance 0.025/0.063 mm (0.0010/0.0025 in.)

Bore I.D.

New

Max. Wear Limit

20.000/20.025 mm (0.7874/0.7884 in.)

20.038 mm (0.7889 in.)

Bearing Surface O.D.

New

Max. Wear Limit

19.962/19.975 mm (0.7859/0.7864 in.)

19.959 mm (0.7858 in.)

Connecting Rod

Connecting Rod-to-Crankpin Running

Clearance

New

Max. Wear Limit

0.030/0.055 mm (0.0012/0.0022 in.)

0.070 mm (0.0028 in.)

Connecting Rod-to-Crankpin Side Clearance 0.26/0.63 mm (0.0102/0.0248 in.)

Connecting Rod-to-Piston Pin Running

Clearance

0.015/0.028 mm (0.0006/0.0011 in.)

Piston Pin End I.D.

New

Max. Wear Limit

17.015/17.023 mm (0.6699/0.6702 in.)

17.036 mm (0.6707 in.)

Values are in Metric units. Values in parentheses are English equivalents.

Lubricate threads with engine oil prior to assembly.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Speciﬁ cations

10 24 690 07 Rev. LKohlerEngines.com

CLEARANCE SPECIFICATIONS

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Crankcase

Governor Cross Shaft Bore I.D.

6 mm Shaft

New

Max. Wear Limit

8 mm Shaft

New

Max. Wear Limit

6.025/6.050 mm (0.2372/0.2382 in.)

6.063 mm (0.2387 in.)

8.025/8.075 mm (0.3159/0.3179 in.)

8.088 mm (0.3184 in.)

Crankshaft

End Play (free) 0.070/0.590 mm (0.0028/0.0230 in.)

Bore (in crankcase)

New

Max. Wear Limit

40.965/41.003 mm (1.6128/1.6143 in.)

41.016 mm (1.6148 in.)

Crankshaft to Sleeve Bearing (crankcase)

Running Clearance - New

0.03/0.09 mm (0.0012/0.0035 in.)

Bore (in oil pan)

New 40.987/40.974 mm (1.6136/1.6131 in.)

Crankshaft Bore (in oil pan)-to-Crankshaft

Running Clearance - New 0.039/0.074 mm (0.0015/0.0029 in.)

Flywheel End Main Bearing Journal

O.D. - New

O.D. - Max. Wear Limit

Max. Taper

Max. Out-of-Round

40.913/40.935 mm (1.6107/1.6116 in.)

40.84 mm (1.608 in.)

0.022 mm (0.0009 in.)

0.025 mm (0.0010 in.)

Oil Pan End Main Bearing Journal

O.D. - New

O.D. - Max. Wear Limit

Max. Taper

Max. Out-of-Round

40.913/40.935 mm (1.6107/1.6116 in.)

40.84 mm (1.608 in.)

0.022 mm (0.0009 in.)

0.025 mm (0.0010 in.)

Connecting Rod Journal

O.D. - New

O.D. - Max. Wear Limit

Max. Taper

Max. Out-of-Round

35.955/35.973 mm (1.4156/1.4163 in.)

35.94 mm (1.415 in.)

0.018 mm (0.0007 in.)

0.025 mm (0.0010 in.)

T.I.R.

PTO End, Crank in Engine

Entire Crank, in V-Blocks

0.279 mm (0.0110 in.)

0.10 mm (0.0039 in.)

Cylinder Bore

Cylinder Bore I.D.

New 73.006/

73.031 mm

(2.8742/

2.8752 in.)

77.000/

77.025 mm

(3.0315/

3.0325 in.)

80.000/

80.025 mm

(3.1496/

3.1506 in.)

82.988/83.013 mm

(3.2672/3.2682 in.)

Max. Wear Limit 73.070 mm

(2.8757 in.)

77.063 mm

(3.0340 in.)

80.065 mm

(3.1522 in.)

83.051 mm (3.2697 in.)

Max. Out-of-Round 0.13 mm

(0.0051 in.)

0.12 mm (0.0047 in.)

Max. Taper 0.05 mm (0.0020 in.)

Cylinder Head

Max. Out-of-Flatness 0.076 mm (0.003 in.) 0.1 mm (0.004 in.)

Values are in Metric units. Values in parentheses are English equivalents.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Speciﬁ cations

1124 690 07 Rev. L KohlerEngines.com

CLEARANCE SPECIFICATIONS

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Governor

Governor Cross Shaft-to-Crankcase Running

Clearance

6 mm Shaft

8 mm Shaft

0.013/0.075 mm (0.0005/0.0030 in.)

0.025/0.126 mm (0.0009/0.0049 in.)

Cross Shaft O.D.

6 mm Shaft

New

Max. Wear Limit

8 mm Shaft

New

Max. Wear Limit

5.975/6.012 mm (0.2352/0.2367 in.)

5.962 mm (0.2347 in.)

7.949/8.000 mm (0.3129/0.3149 in.)

7.936 mm (0.3124 in.)

Governor Gear Shaft-to-Governor Gear

Running Clearance

0.015/0.140 mm (0.0006/0.0055 in.)

Gear Shaft O.D.

New

Max. Wear Limit

5.990/6.000 mm (0.2358/0.2362 in.)

5.977 mm (0.2353 in.)

Ignition

Spark Plug Gap 0.76 mm (0.030 in.)

Module Air Gap 0.28/0.33 mm (0.011/0.013 in.)

Piston, Piston Rings, and Piston Pin

Piston Style A

Piston-to-Piston Pin Running Clearance 0.006/0.017 mm (0.0002/0.0007 in.)

Pin Bore I.D.

New

Max. Wear Limit

17.006/17.012 mm (0.6695/0.6698 in.)

17.025 mm (0.6703 in.)

Pin O.D.

New

Max. Wear Limit

16.995/17.000 mm (0.6691/0.6693 in.)

16.994 mm (0.6691 in.)

Top Compression Ring-to-Groove Side

Clearance

0.040/

0.085 mm

(0.0016/

0.0033 in.)

0.040/

0.080 mm

(0.0016/

0.0031 in.)

0.030/

0.076 mm

(0.0012/

0.0030 in.)

0.025/0.048 mm

(0.0010/0.0019 in.)

Middle Compression Ring-to-Groove Side

Clearance

0.030/

0.080 mm

(0.0012/

0.0031 in.)

0.040/

0.080 mm

(0.0016/

0.0031 in.)

0.030/

0.076 mm

(0.0012/

0.0030 in.)

0.015/0.037 mm\

(0.0006/0.0015 in.)

Oil Control Ring-to-Groove Side Clearance 0.046/

0.201 mm

(0.0018/

0.0079 in.)

0.060/

0.202 mm

(0.0024/

0.0080 in.)

0.046/

0.196 mm

(0.0018/

0.0077 in.)

0.026/0.176 mm

(0.0010/0.0070 in.)

Values are in Metric units. Values in parentheses are English equivalents.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Speciﬁ cations

12 24 690 07 Rev. LKohlerEngines.com

CLEARANCE SPECIFICATIONS

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Piston, Piston Rings, and Piston Pin (Style A continued)

Top and Middle Compression Ring End Gap

New Bore

Top Ring

Middle Ring

0.180/

0.380 mm

(0.0071/

0.0150 in.)

0.180/

0.440 mm

(0.0071/

0.0173 in.)

0.25/

0.45 mm

(0.0098/

0.0177 in.)

---

0.18/

0.46 mm

(0.0071/

0.0181 in.)

---

0.25/0.56 mm

(0.0100/0.0224 in.)

---

Used Bore (Max.)

Top Ring

Middle Ring

0.70 mm

(0.028 in.)

0.90 mm

(0.035 in.)

0.77 mm

(0.030 in.)

---

0.80 mm

(0.0315 in.)

---

0.94 mm (0.037 in.)

---

Thrust Face O.D.

New 72.966/

72.984 mm

(2.8727/

2.8734 in.)

76.943/

76.961 mm

(3.0292/

3.0299 in.)

79.943/

79.961 mm

(3.1473/

3.1480 in.)

82.949/

82.967 mm

(3.2656/

3.2664 in.)

Max. Wear Limit 72.839 mm

(2.8677 in.)

76.816 mm

(3.0242 in.)

79.816 mm

(3.1423 in.)

82.822 mm (3.2606 in.)

Piston Thrust Face-to-Cylinder Bore

Running

Clearance

New 0.022/

0.065 mm

(0.0009/

0.0026 in.)

0.039/0.082 mm

(0.0015/0.0032 in.)

Piston Style B

Piston-to-Piston Pin Running Clearance 0.006/0.017 mm (0.0002/0.0007 in.)

Pin Bore I.D.

New

Max. Wear Limit

17.006/17.012 mm (0.6695/0.6698 in.)

17.025 mm (0.6703 in.)

Pin O.D.

New

Max. Wear Limit

16.995/17.000 mm (0.6691/0.6693 in.)

16.994 mm (0.6691 in.)

Top Compression Ring-to-Groove Side

Clearance 0.030/0.070 mm (0.001/0.0026 in.)

Middle Compression Ring-to-Groove Side

Clearance 0.030/0.070 mm (0.001/0.0026 in.)

Oil Control Ring-to-Groove Side Clearance 0.060/0.190 mm (0.0022/0.0073 in.)

Values are in Metric units. Values in parentheses are English equivalents.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Measure 6 mm (0.24 in.) above bottom of piston skirt at right angles to piston pin.

Speciﬁ cations

1324 690 07 Rev. L KohlerEngines.com

CLEARANCE SPECIFICATIONS

CV17

CV18/CV20/

CV22/

CV620/CV621/

CV640/CV641

CV22/CV23/

CV620

CV640

CV670/CV680

CV25/

CV730/

CV740 CV750

Piston, Piston Rings, and Piston Pin (Style B continued)

Top Compression Ring End Gap

New Bore 0.100/

0.279 mm

(0.0039/

0.0110 in.)

0.189/0.277 mm

(0.0074/0.0109 in.)

Used Bore (Max) 0.490 mm

(0.0192 in.)

0.531 mm (0.0209 in.)

Middle Compression Ring End Gap

New Bore 1.400/

1.679 mm

(0.0551/

0.0661 in.)

1.519/1.797 mm

(0.0598/0.0708 in.)

Used Bore (Max) 1.941 mm

(0.0764 in.)

2.051 mm (0.0808 in.)

Thrust Face O.D.

New 79.966 mm

(3.1483 in.)

82.978 mm

(3.2668 in.)

Max. Wear Limit 79.821 mm

(3.1426 in.)

82.833 mm

(3.2611 in.)

Piston Thrust Face-to-Cylinder Bore Running

Clearance

New

0.025/

0.068 mm

(0.0010/

0.0027 in.)

0.019/0.062 mm

(0.0007/0.0024 in.)

Valves and Valve Lifters

Hydraulic Valve Lifter to Crankcase Running

Clearance

0.0241/0.0501 mm (0.0009/0.0020 in.)

Intake Valve Stem-to-Valve Guide Running

Clearance

0.038/0.076 mm (0.0015/0.0030 in.)

Exhaust Valve Stem-to-Valve Guide Running

Clearance

0.050/0.088 mm (0.0020/0.0035 in.)

Intake Valve Guide I.D.

New

Max. Wear Limit

7.038/7.058 mm (0.2771/0.2779 in.)

7.134 mm (0.2809 in.)

Exhaust Valve Guide I.D.

New

Max. Wear Limit

7.038/7.058 mm (0.2771/0.2779 in.)

7.159 mm (0.2819 in.)

Valve Guide Reamer Size

Standard

0.25 mm O.S.

7.048 mm (0.2775 in.)

7.298 mm (0.2873 in.)

Intake Valve Minimum Lift 8.07 mm (0.3177 in.)

Exhaust Valve Minimum Lift 8.07 mm (0.3177 in.)

Nominal Valve Seat Angle 45°

Values are in Metric units. Values in parentheses are English equivalents.

CV620/CV640 engines changed from 624cc to 674cc; displacement can be conﬁ rmed on engine nameplate.

Measure 6 mm (0.2362 in.) above bottom of piston skirt at right angles to piston pin.

Measure 13 mm (0.5118 in.) above bottom of piston skirt at right angles to piston pin.

Speciﬁ cations

14 24 690 07 Rev. LKohlerEngines.com

GENERAL TORQUE VALUES

Metric Fastener Torque Recommendations for Standard Applications

Property Class

Noncritical

Fasteners

Into Aluminum

Size

4.8

5.8

8.8

10.9 12.9

Tightening Torque: N·m (in. lb.) ± 10%

M4 1.2 (11) 1.7 (15) 2.9 (26) 4.1 (36) 5.0 (44) 2.0 (18)

M5 2.5 (22) 3.2 (28) 5.8 (51) 8.1 (72) 9.7 (86) 4.0 (35)

M6 4.3 (38) 5.7 (50) 9.9 (88) 14.0 (124) 16.5 (146) 6.8 (60)

M8 10.5 (93) 13.6 (120) 24.4 (216) 33.9 (300) 40.7 (360) 17.0 (150)

Tightening Torque: N·m (ft. lb.) ± 10%

M10 21.7 (16) 27.1 (20) 47.5 (35) 66.4 (49) 81.4 (60) 33.9 (25)

M12 36.6 (27) 47.5 (35) 82.7 (61) 116.6 (86) 139.7 (103) 61.0 (45)

M14 58.3 (43) 76.4 (56) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)

Torque Conversions

N·m = in. lb. x 0.113 in. lb. = N·m x 8.85

N·m = ft. lb. x 1.356 ft. lb. = N·m x 0.737

English Fastener Torque Recommendations for Standard Applications

Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel

Grade 2 or 5 Fasteners

Into Aluminum

Size Grade 2 Grade 5 Grade 8

Tightening Torque: N·m (in. lb.) ± 20%

8-32 2.3 (20) 2.8 (25) — 2.3 (20)

10-24 3.6 (32) 4.5 (40) — 3.6 (32)

10-32 3.6 (32) 4.5 (40) — —

1/4-20 7.9 (70) 13.0 (115) 18.7 (165) 7.9 (70)

1/4-28 9.6 (85) 15.8 (140) 22.6 (200) —

5/16-18 17.0 (150) 28.3 (250) 39.6 (350) 17.0 (150)

5/16-24 18.7 (165) 30.5 (270) — —

3/8-16 29.4 (260) — — —

3/8-24 33.9 (300) — — —

Tightening Torque: N·m (ft. lb.) ± 20%

5/16-24 — — 40.7 (30) —

3/8-16 — 47.5 (35) 67.8 (50) —

3/8-24 — 54.2 (40) 81.4 (60) —

7/16-14 47.5 (35) 74.6 (55) 108.5 (80) —

7/16-20 61.0 (45) 101.7 (75) 142.5 (105) —

1/2-13 67.8 (50) 108.5 (80) 155.9 (115) —

1/2-20 94.9 (70) 142.4 (105) 223.7 (165) —

9/16-12 101.7 (75) 169.5 (125) 237.3 (175) —

9/16-18 135.6 (100) 223.7 (165) 311.9 (230) —

5/8-11 149.5 (110) 244.1 (180) 352.6 (260) —

5/8-18 189.8 (140) 311.9 (230) 447.5 (330) —

3/4-10 199.3 (147) 332.2 (245) 474.6 (350) —

3/4-16 271.2 (200) 440.7 (325) 637.3 (470) —

Speciﬁ cations

1524 690 07 Rev. L KohlerEngines.com

Tools and Aids

16 24 690 07 Rev. LKohlerEngines.com

Certain quality tools are designed to help you perform speciﬁ c disassembly, repair, and reassembly procedures. By

using these tools, you can properly service engines easier, faster, and safer! In addition, you’ll increase your service

capabilities and customer satisfaction by decreasing engine downtime.

Here is a list of tools and their source.

SEPARATE TOOL SUPPLIERS

Kohler Tools

Contact your local Kohler source of

supply.

SE Tools

415 Howard St.

Lapeer, MI 48446

Phone 810-664-2981

Toll Free 800-664-2981

Fax 810-664-8181

Design Technology Inc.

768 Burr Oak Drive

Westmont, IL 60559

Phone 630-920-1300

Fax 630-920-0011

TOOLS

Description Source/Part No.

Alcohol Content Tester

For testing alcohol content (%) in reformulated/oxygenated fuels.

Kohler 25 455 11-S

Camshaft Endplay Plate

For checking camshaft endplay.

SE Tools KLR-82405

Camshaft Seal Protector (Aegis)

For protecting seal during camshaft installation.

SE Tools KLR-82417

Cylinder Leakdown Tester

For checking combustion retention and if cylinder, piston, rings, or valves are worn.

Individual component available:

Adapter 12 mm x 14 mm (Required for leakdown test on XT-6 engines)

Kohler 25 761 05-S

Design Technology Inc.

DTI-731-03

Dealer Tool Kit (Domestic)

Complete kit of Kohler required tools.

Components of 25 761 39-S

Ignition System Tester

Cylinder Leakdown Tester

Oil Pressure Test Kit

Rectiﬁ er-Regulator Tester (120 V AC/60Hz)

Kohler 25 761 39-S

Kohler 25 455 01-S

Kohler 25 761 05-S

Kohler 25 761 06-S

Kohler 25 761 20-S

Dealer Tool Kit (International)

Complete kit of Kohler required tools.

Components of 25 761 42-S

Ignition System Tester

Cylinder Leakdown Tester

Oil Pressure Test Kit

Rectiﬁ er-Regulator Tester (240 V AC/50Hz)

Kohler 25 761 42-S

Kohler 25 455 01-S

Kohler 25 761 05-S

Kohler 25 761 06-S

Kohler 25 761 41-S

Digital Vacuum/Pressure Tester

For checking crankcase vacuum.

Individual component available:

Rubber Adapter Plug

Design Technology Inc.

DTI-721-01

Design Technology Inc.

DTI-721-10

Electronic Fuel Injection (EFI) Diagnostic Software

For Laptop or Desktop PC.

Kohler 25 761 23-S

EFI Service Kit

For troubleshooting and setting up an EFI engine.

Components of 24 761 01-S

Fuel Pressure Tester

Noid Light

90° Adapter

Code Plug, Red Wire

Code Plug, Blue Wire

Shrader Valve Adapter Hose

Wire Probe Set (2 pieces regular wire with clip; 1 piece fused wire)

Hose Removal Tool, Dual Size/End (also sold as individual Kohler tool)

K-Line Adapter Jumper Lead Wiring Harness

Kohler 24 761 01-S

Design Technology Inc.

DTI-019

DTI-021

DTI-023

DTI-027

DTI-029

DTI-037

DTI-031

DTI-033

Kohler 25 176 23-S

Kohler Wireless Diagnostic System Module (Bluetooth®)

For wireless Android EFI diagnostics.

Individual component available:

Wireless Diagnostic System Interface Cable

Kohler 25 761 45-S

Kohler 25 761 44-S

Tools and Aids

1724 690 07 Rev. L KohlerEngines.com

TOOLS

Description Source/Part No.

Flywheel Puller

For properly removing ﬂ ywheel from engine.

SE Tools KLR-82408

Hose Removal Tool, Dual Size/End (also available in EFI Service Kit)

Used to properly remove fuel hose from engine components.

Kohler 25 455 20-S

Hydraulic Valve Lifter Tool

For removing and installing hydraulic lifters.

Kohler 25 761 38-S

Ignition System Tester

For testing output on all systems, including CD.

Kohler 25 455 01-S

Inductive Tachometer (Digital)

For checking operating speed (RPM) of an engine.

Design Technology Inc.

DTI-110

Oﬀ set Wrench (K and M Series)

For removing and reinstalling cylinder barrel retaining nuts.

Kohler 52 455 04-S

Oil Pressure Test Kit

For testing/verifying oil pressure on pressure lubricated engines.

Kohler 25 761 06-S

Rectiﬁ er-Regulator Tester (120 volt current)

Rectiﬁ er-Regulator Tester (240 volt current)

For testing rectiﬁ er-regulators.

Components of 25 761 20-S and 25 761 41-S

CS-PRO Regulator Test Harness

Special Regulator Test Harness with Diode

Kohler 25 761 20-S

Kohler 25 761 41-S

Design Technology Inc.

DTI-031R

DTI-033R

Spark Advance Module (SAM) Tester

For testing SAM (ASAM and DSAM) on engines with SMART-SPARK

™

Kohler 25 761 40-S

Starter Servicing Kit (All Starters)

For removing and reinstalling drive retaining rings and brushes.

Individual component available:

Starter Brush Holding Tool (Solenoid Shift)

SE Tools KLR-82411

SE Tools KLR-82416

Stepper Motor Controller Tool

For testing operation of stepper motor/Digital Linear Actuator (DLA).

Kohler 25 455 21-S

Jumper Lead Tool

For use with Stepper Motor Controller Tool to test rotary stepper motor.

Kohler 25 518 43-S

Triad/OHC Timing Tool Set

For holding cam gears and crankshaft in timed position while installing timing belt.

Kohler 28 761 01-S

Valve Guide Reamer (K and M Series)

For properly sizing valve guides after installation.

Design Technology Inc.

DTI-K828

Valve Guide Reamer O.S. (Command Series)

For reaming worn valve guides to accept replacement oversize valves. Can be used

in low-speed drill press or with handle below for hand reaming.

Kohler 25 455 12-S

Reamer Handle

For hand reaming using Kohler 25 455 12-S reamer.

Design Technology Inc.

DTI-K830

AIDS

Description Source/Part No.

Camshaft Lubricant (Valspar ZZ613) Kohler 25 357 14-S

Dielectric Grease (GE/Novaguard G661) Kohler 25 357 11-S

Dielectric Grease Loctite

51360

Kohler Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S

Kohler Electric Starter Drive Lubricant (Solenoid Shift) Kohler 52 357 02-S

RTV Silicone Sealant

Loctite

5900

Heavy Body in 4 oz. aerosol dispenser.

Only oxime-based, oil resistant RTV sealants, such as those listed, are approved

for use. Permatex

the Right Stuﬀ

1 Minute Gasket™ or Loctite

Nos. 5900

5910

are recommended for best sealing characteristics.

Kohler 25 597 07-S

Loctite

5910

Loctite

Ultra Black 598™

Loctite

Ultra Blue 587™

Loctite

Ultra Copper 5920™

Permatex

the Right Stuﬀ

Minute Gasket™

Spline Drive Lubricant Kohler 25 357 12-S

Tools and Aids

18 24 690 07 Rev. LKohlerEngines.com

FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL

A ﬂ ywheel holding tool can be made out of an old junk

ﬂ ywheel ring gear and used in place of a strap wrench.

1. Using an abrasive cut-oﬀ wheel, cut out a six tooth

segment of ring gear as shown.

2. Grind oﬀ any burrs or sharp edges.

3. Invert segment and place it between ignition bosses

on crankcase so tool teeth engage ﬂ ywheel ring

gear teeth. Bosses will lock tool and ﬂ ywheel in

position for loosening, tightening, or removing with a

puller.

A spanner wrench to lift rocker arms or turn crankshaft

may be made out of an old junk connecting rod.

1. Find a used connecting rod from a 10 HP or larger

engine. Remove and discard rod cap.

2. Remove studs of a Posi-Lock rod or grind oﬀ

aligning steps of a Command rod, so joint surface is

ﬂ at.

3. Find a 1 in. long capscrew with correct thread size to

match threads in connecting rod.

4. Use a ﬂ at washer with correct I.D. to slip on

capscrew and approximately 1 in. O.D. Assemble

capscrew and washer to joint surface of rod.

1924 690 07 Rev. L KohlerEngines.com

Troubleshooting

Engine Cranks But Will Not Start

● Battery connected backwards.

● Blown fuse.

● Carburetor solenoid malfunction.

● Choke not closing.

● Clogged fuel line or fuel ﬁ lter.

● Diode in wiring harness failed in open circuit mode.

● DSAI or DSAM malfunction.

● Empty fuel tank.

● Faulty electronic control unit.

● Faulty ignition coil(s).

● Faulty spark plug(s).

● Fuel pump malfunction-vacuum hose clogged or

leaking.

● Fuel shut-oﬀ valve closed.

● Ignition module(s) faulty or improperly gapped.

● Insuﬃ cient voltage to electronic control unit.

● Interlock switch is engaged or faulty.

● Key switch or kill switch in OFF position.

● Low oil level.

● Quality of fuel (dirt, water, stale, mixture).

● SMART-SPARK

malfunction.

● Spark plug lead(s) disconnected.

Engine Starts But Does Not Keep Running

● Faulty carburetor.

● Faulty cylinder head gasket.

● Faulty or misadjusted choke or throttle controls.

● Fuel pump malfunction-vacuum hose clogged or

leaking.

● Intake system leak.

● Loose wires or connections that intermittently ground

ignition kill circuit.

● Quality of fuel (dirt, water, stale, mixture).

● Restricted fuel tank cap vent.

Engine Starts Hard

● Clogged fuel line or fuel ﬁ lter.

● Engine overheated.

● Faulty ACR mechanism.

● Faulty or misadjusted choke or throttle controls.

● Faulty spark plug(s).

● Flywheel key sheared.

● Fuel pump malfunction-vacuum hose clogged or

leaking.

● Interlock switch is engaged or faulty.

● Loose wires or connections that intermittently ground

ignition kill circuit.

● Low compression.

● Quality of fuel (dirt, water, stale, mixture).

● Weak spark.

TROUBLESHOOTING GUIDE

When troubles occur, be sure to check simple causes which, at ﬁ rst, may seem too obvious to be considered. For

example, a starting problem could be caused by an empty fuel tank.

Some general common causes of engine troubles are listed below and vary by engine speciﬁ cation. Use these to

locate causing factors.

Engine Will Not Crank

● Battery is discharged.

● Faulty electric starter or solenoid.

● Faulty key switch or ignition switch.

● Interlock switch is engaged or faulty.

● Loose wires or connections that intermittently ground

ignition kill circuit.

● Pawls not engaging in drive cup.

● Seized internal engine components.

Engine Runs But Misses

● Carburetor adjusted incorrectly.

● Engine overheated.

● Faulty spark plug(s).

● Ignition module(s) faulty or improperly gapped.

● Incorrect crankshaft position sensor air gap.

● Interlock switch is engaged or faulty.

● Loose wires or connections that intermittently ground

ignition kill circuit.

● Quality of fuel (dirt, water, stale, mixture).

● Spark plug lead(s) disconnected.

● Spark plug lead boot loose on plug.

● Spark plug lead loose.

Engine Will Not Idle

● Engine overheated.

● Faulty spark plug(s).

● Idle fuel adjusting needle(s) improperly set.

● Idle speed adjusting screw improperly set.

● Inadequate fuel supply.

● Low compression.

● Quality of fuel (dirt, water, stale, mixture).

● Restricted fuel tank cap vent.

Engine Overheats

● Cooling fan broken.

● Excessive engine load.

● Fan belt failed/oﬀ .

● Faulty carburetor.

● High crankcase oil level.

● Lean fuel mixture.

● Low cooling system ﬂ uid level.

● Low crankcase oil level.

● Radiator, and/or cooling system components clogged,

restricted, or leaking.

● Water pump belt failed/broken.

● Water pump malfunction.

Engine Knocks

● Excessive engine load.

● Hydraulic lifter malfunction.

● Incorrect oil viscosity/type.

● Internal wear or damage.

● Low crankcase oil level.

● Quality of fuel (dirt, water, stale, mixture).

Troubleshooting

20 24 690 07 Rev. LKohlerEngines.com

Engine Loses Power

● Dirty air cleaner element.

● Engine overheated.

● Excessive engine load.

● Restricted exhaust.

● Faulty spark plug(s).

● High crankcase oil level.

● Incorrect governor setting.

● Low battery.

● Low compression.

● Low crankcase oil level.

● Quality of fuel (dirt, water, stale, mixture).

Engine Uses Excessive Amount of Oil

● Loose or improperly torqued fasteners.

● Blown head gasket/overheated.

● Breather reed broken.

● Clogged, broken, or inoperative crankcase breather.

● Crankcase overﬁ lled.

● Incorrect oil viscosity/type.

● Worn cylinder bore.

● Worn or broken piston rings.

● Worn valve stems/valve guides.

Oil Leaks from Oil Seals, Gaskets

● Breather reed broken.

● Clogged, broken, or inoperative crankcase breather.

● Loose or improperly torqued fasteners.

● Piston blow by, or leaky valves.

● Restricted exhaust.

EXTERNAL ENGINE INSPECTION

NOTE: It is good practice to drain oil at a location away

from workbench. Be sure to allow ample time for

complete drainage.

Before cleaning or disassembling engine, make a

thorough inspection of its external appearance and

condition. This inspection can give clues to what might

be found inside engines (and cause) when it is

disassembled.

● Check for buildup of dirt and debris on crankcase,

cooling ﬁ ns, grass screen, and other external surfaces.

Dirt or debris on these areas can cause overheating.

● Check for obvious fuel and oil leaks, and damaged

components. Excessive oil leakage can indicate a

clogged or inoperative breather, worn or damaged

seals or gaskets, or loose fasteners.

● Check air cleaner cover and base for damage or

indications of improper ﬁ t and seal.

● Check air cleaner element. Look for holes, tears,

cracked or damaged sealing surfaces, or other

damage that could allow unﬁ ltered air into engine. A

dirty or clogged element could indicate insuﬃ cient or

improper maintenance.

● Check carburetor throat for dirt. Dirt in throat is further

indication that air cleaner was not functioning properly.

● Check if oil level is within operating range on dipstick.

If it is above, sniﬀ for gasoline odor.

● Check condition of oil. Drain oil into a container; it

should ﬂ ow freely. Check for metal chips and other

foreign particles.

Sludge is a natural by-product of combustion; a small

accumulation is normal. Excessive sludge formation

could indicate over rich fuel settings, weak ignition,

overextended oil change interval or wrong weight or

type of oil was used.

CLEANING ENGINE

WARNING

Cleaning Solvents can cause severe injury or

death.

Use only in well ventilated areas away from

ignition sources.

Carburetor cleaners and solvents are extremely

ﬂ ammable. Follow cleaner manufacturer’s warnings

and instructions on its proper and safe use. Never use

gasoline as a cleaning agent.

After inspecting external condition of engine, clean

engine thoroughly before disassembly. Clean individual

components as engine is disassembled. Only clean

parts can be accurately inspected and gauged for wear

or damage. There are many commercially available

cleaners that will quickly remove grease, oil, and grime

from engine parts. When such a cleaner is used, follow

manufacturer’s instructions and safety precautions

carefully.

Make sure all traces of cleaner are removed before

engine is reassembled and placed into operation. Even

small amounts of these cleaners can quickly break down

lubricating properties of engine oil.

2124 690 07 Rev. L KohlerEngines.com

Troubleshooting

Condition Conclusion

Crankcase breather clogged or inoperative. NOTE: If breather is integral part of valve cover and

cannot be serviced separately, replace valve

cover and recheck pressure.

Disassemble breather, clean parts thoroughly, check

sealing surfaces for ﬂ atness, reassemble, and recheck

pressure.

Seals and/or gaskets leaking. Loose or improperly torque

fasteners.

Replace all worn or damaged seals and gaskets. Make

sure all fasteners are tightened securely. Use appropriate

torque valves and sequences when necessary.

Piston blow by or leaky valves (conﬁ rm by inspecting

components).

Recondition piston, rings, cylinder bore, valves and

valves guides.

Restricted exhaust. Check exhaust screen/spark arrestor (if equipped). Clean

or replace as needed. Repair or replace any other

damaged/restricted muﬄ er or exhaust system parts.

CRANKCASE VACUUM TEST

WARNING

Carbon Monoxide can cause severe nausea,

fainting or death.

Avoid inhaling exhaust fumes. Never run

engine indoors or in enclosed spaces.

Engine exhaust gases contain poisonous carbon

monoxide. Carbon monoxide is odorless, colorless,

and can cause death if inhaled.

To test crankcase vacuum with manometer:

1. Insert rubber stopper into oil ﬁ ll hole. Be sure pinch

clamp is installed on hose and use tapered adapters

to connect hose between stopper and one

manometer tube. Leave other tube open to

atmosphere. Check that water level in manometer is

at 0 line. Make sure pinch clamp is closed.

2. Start engine and run no-load high speed.

3. Open clamp and note water level in tube.

Level in engine side should be a minimum of

10.2 cm (4 in.) above level in open side.

If level in engine side is less than speciﬁ ed (low/no

vacuum), or level in engine side is lower than level in

open side (pressure), check for conditions in table

below.

4. Close pinch clamp before stopping engine.

To test crankcase vacuum with vacuum/pressure gauge:

1. Remove dipstick or oil ﬁ ll plug/cap.

2. Install adapter into oil ﬁ ll/dipstick tube opening,

upside down over end of a small diameter dipstick

tube, or directly into engine if a tube is not used.

Insert barbed gauge ﬁ tting into hole in stopper.

3. Run engine and observe gauge reading.

Analog tester–needle movement to left of 0 is a

vacuum, and movement to right indicates a pressure.

Digital tester–depress test button on top of tester.

Crankcase vacuum should be a minimum of 10.2 cm

(4 in.) of water. If reading is below speciﬁ cation, or if

pressure is present, check table below for possible

causes and conclusions.

WARNING

Rotating Parts can cause severe injury.

Stay away while engine is in operation.

Keep hands, feet, hair, and clothing away from all

moving parts to prevent injury. Never operate engine

with covers, shrouds, or guards removed.

A partial vacuum should be present in crankcase when engine is operating. Pressure in crankcase (normally caused

by a clogged or improperly assembled breather) can cause oil to be forced out at oil seals, gaskets, or other available

spots.

Crankcase vacuum is best measured with either a water manometer or a vacuum gauge. Complete instructions are

provided in kits.

Troubleshooting

22 24 690 07 Rev. LKohlerEngines.com

COMPRESSION TEST

For Command Twins:

A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s)

before removing them. Be sure choke is oﬀ , and throttle is wide open during test. Compression should be at least 160

psi and should not vary more than 15% between cylinders.

All other models:

These engines are equipped with an automatic compression release (ACR) mechanism. It is diﬃ cult to obtain an

accurate compression reading because of ACR mechanism. As an alternative, use cylinder leakdown test described

below.

CYLINDER LEAKDOWN TEST

A cylinder leakdown test can be a valuable alternative to a compression test. By pressurizing combustion chamber

from an external air source you can determine if valves or rings are leaking, and how badly.

Cylinder leakdown tester is a relatively simple, inexpensive leakdown tester for small engines. This tester includes a

quick-connect for attaching adapter hose and a holding tool.

1. Run engine for 3-5 minutes to warm it up.

2. Remove spark plug(s) and air ﬁ lter from engine.

3. Rotate crankshaft until piston (of cylinder being tested) is at top dead center (TDC) of compression stroke. Hold

engine in this position while testing. Holding tool supplied with tester can be used if PTO end of crankshaft is

accessible. Lock holding tool onto crankshaft. Install a 3/8 in. breaker bar into hole/slot of holding tool, so it is

perpendicular to both holding tool and crankshaft PTO.

If ﬂ ywheel end is more accessible, use a breaker bar and socket on ﬂ ywheel nut/screw to hold it in position. An

assistant may be needed to hold breaker bar during testing. If engine is mounted in a piece of equipment, it may

be possible to hold it by clamping or wedging a driven component. Just be certain that engine cannot rotate oﬀ of

TDC in either direction.

4. Install adapter into spark plug hole, but do not attach it to tester at this time.

5. Turn regulator knob completely counterclockwise.

6. Connect an air source of at least 50 psi to tester.

7. Turn regulator knob clockwise (increase direction) until gauge needle is in yellow set area at low end of scale.

8. Connect tester quick-connect to adapter hose. While ﬁ rmly holding engine at TDC, gradually open tester valve.

Note gauge reading and listen for escaping air at combustion air intake, exhaust outlet, and crankcase breather.

Condition Conclusion

Air escaping from crankcase breather. Ring or cylinder worn.

Air escaping from exhaust system. Defective exhaust valve/improper seating.

Air escaping from intake. Defective intake valve/improper seating.

Gauge reading in low (green) zone. Piston rings and cylinder in good condition.

Gauge reading in moderate (yellow) zone. Engine is still usable, but there is some wear present.

Customer should start planning for overhaul or

replacement.

Gauge reading in high (red) zone. Rings and/or cylinder have considerable wear. Engine

should be reconditioned or replaced.

Air Cleaner/Intake

24 690 07 Rev. L KohlerEngines.com

AIR CLEANER

These systems are CARB/EPA certiﬁ ed and components

should not be altered or modiﬁ ed in any way.

Low-Proﬁ le and Commercial Mower Air Cleaner

Components

A Air Cleaner Cover B Air Cleaner Knob

C Wing Nut D Element Cover

E Rubber Seal F Precleaner

G Paper Element H Air Cleaner Base

I Element Cover Nut J Rubber Seal

K Stud

Heavy-Duty Air Cleaner Components

L Air Cleaner Housing M Element

N End Cap O Dust Ejector Valve

P Retaining Clip Q Inner Element

R Ejector Area S Inlet Screen

T Filter Minder

NOTE: Operating engine with loose or damaged air

cleaner components could cause premature

wear and failure. Replace all bent or damaged

components.

NOTE: Paper element cannot be blown out with

compressed air.

Low-Proﬁ le/Commercial Mower

Loosen knob and remove air cleaner cover.

Precleaner

1. Remove precleaner from paper element.

2. Replace or wash precleaner in warm water with

detergent. Rinse and allow to air dry.

3. Saturate precleaner with new engine oil; squeeze

out excess oil.

4. Reinstall precleaner over paper element.

Paper Element

1. Clean area around element. Remove wing nut,

element cover, and paper element with precleaner.

2. Separate precleaner from element; service

precleaner and replace paper element.

3. Check condition of rubber seal and replace if

necessary.

4. Install new paper element on base; install precleaner

over paper element; reinstall element cover and

secure with wing nut.

Reinstall air cleaner cover and secure with knob.

Heavy-Duty

1. Unhook retaining clips and remove end cap(s).

2. Check and clean inlet screen (if equipped).

3. Pull air cleaner element out of housing and replace.

Check condition of inner element; replace when

dirty.

4. Check all parts for wear, cracks, or damage, and that

ejector area is clean.

5. Install new element(s).

6. Reinstall end cap(s) with dust ejector valve/screen

down; secure with retaining clips.

BREATHER TUBE

Ensure sure both ends of breather tube are properly

connected.

AIR COOLING

WARNING

Hot Parts can cause severe burns.

Do not touch engine while operating or just

after stopping.

Never operate engine with heat shields or guards

removed.

Proper cooling is essential. To prevent over heating,

clean screens, cooling ﬁ ns, and other external surfaces

of engine. Avoid spraying water at wiring harness or any

electrical components. Refer to Maintenance Schedule.

Fuel System

24 690 07 Rev. L

KohlerEngines.com

Typical carbureted fuel system and related components

include:

● Fuel tank and valve.

● Fuel lines.

● In-line fuel ﬁ lter.

● Fuel pump.

● Carburetor.

Fuel from tank is moved through in-line ﬁ lter and fuel

lines by fuel pump. Fuel then enters carburetor ﬂ oat bowl

and is drawn into carburetor body and mixed with air.

This fuel-air mixture is then burned in engine combustion

chamber.

FUEL RECOMMENDATIONS

Refer to Maintenance.

FUEL LINE

Low permeation fuel line must be installed on carbureted

Kohler Co. engines to maintain EPA and CARB

regulatory compliance.

FUEL PUMP

Some engines use a pulse style fuel pump. Pumping

action of pulse style pumps is created by oscillation of

positive and negative pressures within crankcase. This

pressure is transmitted to pulse pump through rubber

hose connected between pump and crankcase. Pumping

action causes diaphragm on inside of pump to pull fuel

in on its downward stroke and to push it into carburetor

on its upward stroke. Two check valves prevent fuel from

going backward through pump.

FUEL SYSTEM TESTS

When engine starts hard or turns over but will not start, fuel system might be causing problems. Test fuel system by

performing following test.

1. Check for fuel in combustion chamber.

a. Disconnect and ground spark plug leads.

b. Close choke on carburetor.

c. Crank engine several times.

d. Remove spark plug and check for fuel at tip.

2. Check for fuel ﬂ ow from tank to fuel pump.

a. Remove fuel line from inlet ﬁ tting of fuel pump.

b. Hold line below bottom of tank. Open shut-oﬀ

valve (if equipped) and observe ﬂ ow.

Performance

Minimum fuel delivery rate must be 7.5 L/hr. (2 gal./hr.)

with a pressure at 0.3 psi and a fuel lift of 24 in. A 1.3 L/

hr. (0.34 gal./hr.) fuel rate must be maintained at 5 Hz.

Fuel Pump Replacement

NOTE: Make sure orientation of new pump is consistent

with removed pump. Internal damage may occur

if installed incorrectly.

Replacement pumps are available through your source

of supply. To replace pulse pump follow these steps.

Note orientation of pump before removing.

1. Disconnect fuel lines from inlet and outlet ﬁ ttings.

2. Remove screws (securing pump) and fuel pump.

3. Remove pulse line that connects pump to

crankcase.

4. Install a new pump using screws.

5. Connect pulse line between pump and crankcase.

6. Torque screws to 2.3 N·m (20 in. lb.).

7. Connect fuel lines to inlet and outlet ﬁ ttings.

3. Check operation of fuel pump.

a. Remove fuel line from inlet ﬁ tting of carburetor.

b. Crank engine several times and observe ﬂ ow.

Condition Conclusion

Fuel at tip of spark plug. Fuel is reaching combustion chamber.

No fuel at tip of spark plug. Check fuel ﬂ ow from fuel tank (step 2).

Fuel ﬂ ows from fuel line. Check for faulty fuel pump (step 3).

If fuel pump is working, check for faulty carburetor. Refer

to Carburetor.

No fuel ﬂ ow from fuel line. Check fuel tank cap vent, fuel pickup screen, in-line

ﬁ lter, shut-oﬀ valve, and fuel line. Correct any observed

problem and reconnect line.

Fuel line condition. Check for a clogged fuel line. If fuel line is unobstructed,

check for overﬁ lled crankcase and/or oil in pulse line. If

checks don't reveal cause of problem, replace pump.

Fuel System

24 690 07 Rev. L

KohlerEngines.com 25

CARBURETORS

WARNING

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings, away

from sparks or ﬂ ames. Spilled fuel could ignite if it comes

in contact with hot parts or sparks from ignition. Never use

gasoline as a cleaning agent.

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Keihin Two-Barrel Carburetor Components

Carburetor Body

Subassembly

Idle Speed

Screw

Idle Speed

Spring

D Screw E Ground Lead

Retaining

Washer

Slow Jet-

Right Side

Slow Jet-

Left Side

O-ring

(Slow Jet)

J Fuel Bowl

O-ring (Fuel

Bowl-Upper)

O-ring (Fuel

Bowl-Lower)

M Drain Screw N Bowl Screw O Fuel Solenoid

P Sealing Washer Q Float R Pin S Screw T Float Clip

Float Valve/

Inlet Needle

Main Nozzle-

Right Side

Main Nozzle-

Left Side

Main Jet-

Right Side

Main Jet-

Left Side

Z Choke Dust Cap AA Choke Shaft AB Spring AC Bushing AD Choke Lever

AE Choke Plate AF

Choke Plate

Screw

Fuel System

24 690 07 Rev. L

KohlerEngines.com

Nikki One-Barrel Carburetor Components

A Carburetor Body B

Idle Fuel

Adjusting Screw

Idle Fuel

Adjusting Spring

D Passage Cover

E Cover Gasket F

Cover Retaining

Screw

G Main Jet H

Ground Lead

(Solenoid Only)

I Fuel Bowl Gasket J Float Kit

K Fuel Bowl L

Bowl Retaining

Screw Gasket

Bowl Retaining

Screw

Shut-oﬀ Solenoid

Assembly

O Throttle Shaft/Lever P Throttle Plate

Q Choke Shaft R Choke Plate

S Air Filter T Collar

U Spring V Ring

W Choke Lever X Idle Speed Screw

Y Idle Speed Spring Z Setscrews

CV17-740 engines in this series are equipped with either

a Nikki or Keihin one-barrel, ﬁ xed main jet carburetor.

Some applications use a fuel shut-oﬀ solenoid installed

in place of fuel bowl retaining screw, and also an

accelerator pump. All carburetors feature a self-relieving

choke.

CV750 engines in this series are equipped with a Keihin

two-barrel side draft design with ﬁ xed main jets. A self-

relieving choke similar to that used on single venturi

carburetors is also contained in design.

Troubleshooting Checklist

When engine starts hard, runs roughly or stalls at low

idle speed, check following areas before adjusting or

disassembling carburetor.

1. Make sure fuel tank is ﬁ lled with clean, fresh

gasoline.

2. Make sure fuel tank cap vent is not blocked and that

it is operating properly.

3. Make sure fuel is reaching carburetor. This includes

checking fuel shut-oﬀ valve, fuel tank ﬁ lter screen,

in-line fuel ﬁ lter, fuel lines and fuel pump for

restrictions or faulty components as necessary.

4. Make sure air cleaner base and carburetor are

securely fastened to engine using gaskets in good

condition.

Keihin One-Barrel Carburetor Components

A Idle Speed Screw B

Idle Fuel

Adjusting Screw

C Carburetor Body D Idle Jet

E Plug F Main Jet

G Float H

Shut-oﬀ Solenoid

Assembly

I Fuel Bowl J Choke Lever

Fuel System

24 690 07 Rev. L

KohlerEngines.com 27

Troubleshooting-Carburetor Related Causes

Condition Possible Cause Conclusion

Engine starts hard, runs rough, or

stalls at idle speed.

Low idle fuel mixture/speed

improperly adjusted.

Adjust low idle speed tab, then adjust

low idle fuel needle.

Engine runs rich (indicated by black,

sooty exhaust smoke, misﬁ ring, loss

of speed and power, governor

hunting, or excessive throttle

opening).

Clogged air cleaner. Clean or replace air cleaner.

Choke partially closed during

operation.

Check choke lever/linkage to ensure

choke is operating properly.

Low idle fuel mixture is improperly

adjusted.

Adjust low idle fuel needle.

Float level is set too high. Separate fuel bowl from carburetor

body. Free (if stuck), or replace ﬂ oat.

Dirt under fuel inlet needle. Remove needle; clean needle and

seat and blow with compressed air.

Bowl vent or air bleeds plugged. Remove low idle fuel adjusting

needle. Clean vent, ports, and air

bleeds. Blow out all passages with

compressed air.

Leaky, cracked, or damaged ﬂ oat. Submerge ﬂ oat to check for leaks.

Engine runs lean (indicated by

misﬁ ring, loss of speed and power,

governor hunting, or excessive

throttle opening).

Low idle fuel mixture is improperly

adjusted.

Adjust low idle fuel needle.

Float level is set too low. Separate fuel bowl from carburetor

body. Free (if stuck), or replace ﬂ oat.

Idle holes plugged; dirt in fuel delivery

channels.

Remove low idle fuel adjusting

needle. Clean main fuel jet and all

passages; blow out with compressed

air.

Fuel leaks from carburetor. Float stuck. Separate fuel bowl from carburetor

body. Free (if stuck), or replace ﬂ oat.

Dirt under fuel inlet needle. Remove needle; clean needle and

seat and blow with compressed air.

Bowl vents plugged. Blow out with compressed air.

Carburetor bowl gasket leaks. Replace gasket.

Fuel Shut-Oﬀ Solenoid

Most carburetors are equipped with a fuel shut-oﬀ solenoid. Solenoid is attached to fuel bowl. Solenoid has a spring-

loaded pin that retracts when 12 volts is applied to lead, allowing fuel ﬂ ow to main jet. When current is removed, pin

extends blocking fuel ﬂ ow.

Below is a simple test, performed with engine oﬀ , that can determine if solenoid is functioning properly:

1. Shut oﬀ fuel and remove solenoid from carburetor. When solenoid is loosened and removed, gas will leak out of

carburetor. Have a container ready to catch fuel.

2. Wipe tip of solenoid with a shop towel or blow with compressed air to remove any remaining fuel. Take solenoid to

a location with good ventilation and no fuel vapors present. You will also need a 12 volt power source that can be

switched on and oﬀ .

3. Be sure power source is switched OFF. Connect positive power source lead to red lead of solenoid. Connect

negative power source lead to solenoid body.

4. Turn power source ON and observe pin in center of solenoid. Pin should retract with power ON and return to its

original position with power OFF. Test several times to verify operation.

5. Make sure air cleaner element (including precleaner if equipped) is clean and all air cleaner components are

fastened securely.

6. Make sure ignition system, governor system, exhaust system, and throttle and choke controls are operating

properly.

Fuel System

24 690 07 Rev. L

KohlerEngines.com

Carburetor Circuits

Float

Fuel level in bowl is maintained by ﬂ oat and fuel inlet

needle. Buoyant force of ﬂ oat stops fuel ﬂ ow when

engine is at rest. When fuel is being consumed, ﬂ oat will

drop and fuel pressure will push inlet needle away from

seat, allowing more fuel to enter bowl. When demand

ceases, buoyant force of ﬂ oat will again overcome fuel

pressure, rising to predetermined setting and stop ﬂ ow.

Slow and Mid-Range

At low speeds engine operates only on slow circuit. As

a metered amount of air is drawn through slow air bleed

jets, fuel is drawn through main jet and further metered

through slow jet. Air and fuel are mixed in body of slow

jet and exit to idle progression (transfer port) chamber.

From idle progression chamber, air fuel mixture is

metered through idle port passage. At low idle air/fuel

mixture is controlled by setting of idle fuel adjusting

screws. This mixture is then mixed with main body of

air and delivered to engine. As throttle plate opening

increases, greater amounts of air/fuel mixture are drawn

in through ﬁ xed and metered idle progression holes.

As throttle plate opens further, vacuum signal becomes

great enough at venturi so main circuit begins to work.

Main (high-speed)

At high speeds/loads engine operates on main circuit.

As a metered amount of air is drawn through air jet,

fuel is drawn through main jet. Air and fuel are mixed

in main nozzles then enters main body of airﬂ ow where

further mixing of fuel and air occurs. This mixture is then

delivered to combustion chamber. Carburetor has a ﬁ xed

main circuit; no adjustment is possible.

Carburetor Adjustments

NOTE: Carburetor adjustments should be made only

after engine has warmed up.

Carburetor is designed to deliver correct fuel-to-air

mixture to engine under all operating conditions. Main

fuel jet is calibrated at factory and is not adjustable.

Idle fuel adjusting needles are also set at factory and

normally do not need adjustment.

Low Idle Speed (RPM) Adjustment

NOTE: Actual low idle speed depends on application.

Refer to equipment manufacturer’s

recommendations. Low idle speed for basic

engines is 1200 RPM.

Place throttle control into idle or slow position. Turn low

idle speed adjusting screw in or out to obtain allow idle

speed of 1200 RPM (± 75 RPM).

Governed Idle Speed Adjustment (If equipped)

1. Hold governor lever away from carburetor so throttle

lever is against idle speed (RPM) adjustment screw

of carburetor. Start engine and allow to warm up,

then adjust screw to set approximately 1200 RPM.

Check speed using a tachometer. Turn adjustment

screw (inner) clockwise (in) to increase or

counterclockwise (out) to decrease speed.

2. Release governor lever and check that throttle lever

is in idle position. Turn governed idle adjustment

screw to obtain equipment manufacturer’s

recommended idle speed (1500-1800 RPM). Some

engines have a bendable tab that is used to set this

speed. A pliers should be used to bend this tab to

achieve recommended speed. Governed idle speed

(RPM) is typically 300 RPM (approximate) higher

than low idle speed.

3. Move throttle lever to wide-open/full throttle position

and hold in this position. Turn high speed screw to

obtain intended high speed no-load RPM. Governed

idle speed must be set before making this

adjustment.

Low Idle Fuel Adjustment

Optimum Low Idle Fuel Setting

A Rich B Lean

C Midpoint D Left Side

E Right Side

NOTE: Engines will have ﬁ xed low idle or limiter caps

on idle fuel adjusting needles. Step 2 can only

be performed within limits allowed by cap. Do

not attempt to remove limiter caps.

1. Place throttle control into idle or slow position. Adjust

low idle speed to 1200 RPM. Follow Low Idle Speed

(RPM) Adjustment.

2. Low idle fuel needle(s) setting: place throttle into idle

or slow position.

a. Turn 1 low idle fuel adjusting needle out

(counterclockwise) from preliminary setting until

engine speed decreases (rich). Note position of

needle. Now turn adjusting needle in (clockwise).

Engine speed may increase, then it will decrease

as needle is turned in (lean). Note position of

needle. Set adjusting needle midway between

rich and lean settings.

b. Repeat procedure on other low idle adjustment

needle (two-barrel carburetor only).

3. Recheck/adjust Low Idle Speed (RPM) to speciﬁed

setting.

Fuel System

24 690 07 Rev. L

KohlerEngines.com 29

High Speed (RPM) Adjustment

1. With engine running, move throttle control to fast.

2. Turn inner adjustment screw outward to decrease, or

inward to increase RPM speed. Courage singles

require loosening screws on speed control bracket

and sliding towards carburetor to lower and away

from carburetor to increase speed.

Carburetor Servicing

WARNING

Accidental Starts can cause severe injury or

death.

Disconnect and ground spark plug lead(s)

before servicing.

Before working on engine or equipment, disable

engine as follows: 1) Disconnect spark plug lead(s). 2)

Disconnect negative (–) battery cable from battery.

NOTE: Main and slow jets are ﬁ xed and size speciﬁ c

and can be removed if required. Fixed jets for

high altitudes are available.

● Inspect carburetor body for cracks, holes, and other

wear or damage.

● Inspect ﬂ oat for cracks, holes, and missing or

damaged ﬂ oat tabs. Check ﬂ oat hinge and shaft for

wear or damage.

● Inspect fuel inlet needle and seat for wear or damage.

● Inspect spring loaded choke plate to make sure it

moves freely on shaft.

1. Perform removal procedures for appropriate air

cleaner and carburetor outlined in Disassembly.

2. Clean exterior surfaces of dirt or foreign material

before disassembling carburetor. Remove bowl

retaining screws, or solenoid assembly on most

single cylinder engines, and carefully separate fuel

bowl from carburetor. Do not damage fuel bowl

O-rings. Transfer any remaining fuel into an

approved container. Save all parts. Fuel can also be

drained prior to bowl removal by loosening/removing

bowl drain screw.

3. Remove ﬂ oat pin (some carburetors may have a

screw which requires removal), and inlet needle.

Seat for inlet needle is not serviceable and should

not be removed.

4. Clean carburetor bowl and inlet seat areas as

required.

5. Carefully remove main jets from carburetor. For

two-barrel carburetors, note and mark jets by

location for proper reassembly. Main jets may be

size/side speciﬁ c. After main jets are removed, on

some carburetors, main nozzles can be removed

through bottom of main towers. Note orientation/

direction of nozzles. End with 2 raised shoulders

should be out/down adjacent to main jets. Save

parts for cleaning and reuse.

6. Position of slow jet varies and is removable only on

some styles of carburetors. See correct illustration

for corresponding style of carburetor showing

location. (On two-barrel carburetors, slow jets may

be sized to speciﬁ c side. Mark or tag jets for proper

reassembly. Note small O-ring on bottom of each

jet.) Save parts for cleaning and reuse unless a jet

kit is also being installed. Clean slow jets using

compressed air. Do not use wire or carburetor

cleaner.

Carburetor is now disassembled for appropriate cleaning

and installation of parts in overhaul kit. See instructions

provided with repair kits for more detailed information.

High Altitude Operation

If this engine is operated at an altitude of 4000 ft.

(1219 meters) or above, a high altitude carburetor

kit is required. To obtain high altitude carburetor kit

information or to ﬁ nd a Kohler authorized dealer, visit

KohlerEngines.com or call 1-800-544-2444 (U.S. and

Canada).

This engine should be operated in its original

conﬁ guration below 4000 ft. (1219 meters).

Operating this engine with the wrong engine

conﬁ guration at a given altitude may increase its

emissions, decrease fuel eﬃ ciency and performance,

and result in damage to the engine.

Governor System

24 690 07 Rev. L

KohlerEngines.com

GOVERNOR

Engine is equipped with a centrifugal ﬂ yweight

mechanical governor. It is designed to hold engine

speed constant under changing load conditions.

Governor gear/ﬂ yweight mechanism is mounted inside

crankcase on oil pan, and is driven oﬀ gear on camshaft.

Governor Components

A Throttle Lever B Control Bracket

C Choke Linkage D Throttle Linkage

E Governor Lever F Governor Spring

Locking Tab

Thrust Washer

H Governor Gear Shaft

I Governor Gear J Regulating Pin

Governor works as follows:

● Centrifugal force acting on rotating governor gear

assembly causes ﬂ yweights to move outward as

speed increases. Governor spring tension moves

them inward as speed decreases.

● As ﬂ yweights move outward, they cause regulating pin

to move outward.

● Regulating pin contacts tab on cross shaft causing

shaft to rotate. One end of cross shaft protrudes

through crankcase. Rotating action of cross shaft is

transmitted to throttle lever of carburetor through

external linkage.

● When engine is at rest, and throttle is in FAST

position, tension of governor spring holds throttle plate

open. When engine is operating, governor gear

assembly is rotating. Force applied by regulating pin

against cross shaft tends to close throttle plate.

Governor spring tension and force applied by

regulating pin balance each other during operation, to

maintain engine speed.

● When load is applied and engine speed and governor

gear speed decreases, governor spring tension moves

governor lever to open throttle plate wider. This allows

more fuel into engine, increasing engine speed. As

speed reaches governed setting, governor spring

tension and force applied by regulating pin will again

oﬀ set each other to hold a steady engine speed.

Governor Adjustments

NOTE: Do not tamper with governor setting. Overspeed

is hazardous and could cause personal injury.

Initial Adjustment Procedure

Make this adjustment whenever governor arm is

loosened or removed from cross shaft. Adjust as follows:

1. Make sure throttle linkage is connected to governor

arm and throttle lever on carburetor.

2. Loosen nut holding governor lever to cross shaft.

3. Move governor lever toward carburetor as far as it

will go (wide open throttle) and hold in this position.

4. Insert a long thin rod or tool into hole on cross shaft

and rotate shaft counterclockwise (viewed from end)

as far as it will turn, then torque nut to 6.8 N·m (60

in. lb.).

Sensitivity Adjustment

Governor sensitivity is adjusted by repositioning

governor spring in holes of governor lever. If speed

surging occurs with a change in engine load, governor

is set too sensitive. If a big drop in speed occurs when

normal load is applied, governor should be set for

greater sensitivity. Adjust as follows:

1. To increase sensitivity, move spring closer to

governor lever pivot point.

2. To decrease sensitivity, move spring away from

governor lever pivot point.

COMMERCIAL MOWER GOVERNOR

ARRANGEMENT

Commercial mower governor arrangement is used

primarily on wide area walk behind mower applications.

Initial adjustment and sensitivity adjustment is same

as for standard governor. Should governor spring be

disconnected from throttle lever and governor lever,

reconnect it as follows:

1. Hook long end of spring through hole in lever from

left side.

2. Rotate spring 180° until hooked.

3. Hook short end of spring into appropriate hole in

governor lever. Refer to Reassembly for correct hole

to use for speed involved.

Inside Engine

Lubrication System

3124 690 07 Rev. L KohlerEngines.com

This engine uses a full pressure lubrication system

which delivers oil under pressure to crankshaft,

camshaft, connecting rod bearing surfaces, and

hydraulic valve lifters.

A high-eﬃ ciency gerotor oil pump maintains high oil ﬂ ow

and oil pressure, even at low speeds and high operating

temperatures. A pressure relief valve limits maximum

pressure of system. Oil pan must be removed to service

oil pickup, pressure relief valve, and oil pump.

Lubrication Components

A Oil Fill/Dipstick B Oil Fill Tube

C Back Side D Oil Filter

E Nipple F Oil Cooler

G O-ring H Oil Drain Plug

I Oil Sentry™

OIL RECOMMENDATIONS

Refer to Maintenance.

CHECK OIL LEVEL

NOTE: To prevent extensive engine wear or damage,

never run engine with oil level below or above

operating range indicator on dipstick.

Ensure engine is cool. Clean oil ﬁ ll/dipstick areas of any

debris.

1. Remove dipstick; wipe oil oﬀ .

2. Reinsert dipstick into tube; rest cap on tube, do not

thread cap onto tube.

3. Remove dipstick; check oil level. Level should be at

top of indicator on dipstick.

4. If oil is low on indicator, add oil up to top of indicator

mark.

5. Reinstall dipstick and tighten securely.

CHANGE OIL AND FILTER

Change oil while engine is warm.

1. Clean area around oil ﬁ ll cap/dipstick, drain plug/oil

drain valve.

a. Remove drain plug and oil ﬁ ll cap/dipstick. Allow

oil to drain completely.

b. Open oil drain valve cap; if needed, attach a

length of 1/2 in. I.D. hose to direct oil into

appropriate container; twist valve drain body

counterclockwise and pull. Remove dipstick.

Allow oil to drain completely.

2. Clean area around oil ﬁ lter. Place a container under

ﬁ lter to catch any oil and remove ﬁ lter. Wipe oﬀ

mounting surface.

a. Reinstall drain plug. Torque to 13.6 N·m

(10 ft. lb.).

b. Close oil drain valve body, remove hose (if used),

and replace cap.

3. Place new ﬁ lter in shallow pan with open end up. Fill

with new oil until oil reaches bottom of threads. Allow

2 minutes for oil to be absorbed by ﬁ lter material.

4. Apply a thin ﬁ lm of clean oil to rubber gasket on new

ﬁ lter.

5. Refer to instructions on oil ﬁ lter for proper

installation.

6. Fill crankcase with new oil. Level should be at top of

indicator on dipstick.

7. Reinstall oil ﬁ ll cap/dipstick and tighten securely.

8. Start engine; check for oil leaks. Stop engine; correct

leaks. Recheck oil level.

9. Dispose of used oil and ﬁ lter in accordance with

local ordinances.

OIL COOLER (if equipped)

Blower Housing Mounted Oil Cooler

1. Clean ﬁ ns with a brush or compressed air.

2. Remove screws securing oil cooler and tilt to clean

back side.

3. Reinstall oil cooler.

Crankcase Mounted Oil Cooler

Clean ﬁ ns with a brush or compressed air.

OIL SENTRY

™

(if equipped)

This switch is designed to prevent engine from starting

in a low oil or no oil condition. Oil Sentry

™

may not shut

down a running engine before damage occurs. In some

applications this switch may activate a warning signal.

Read your equipment manuals for more information.

Oil Sentry

™

pressure switch is installed in breather cover.

On engines not equipped with Oil Sentry

™

installation

hole is sealed with a 1/8-27 N.P.T.F. pipe plug.

24 690 07 Rev. LKohlerEngines.com32

Lubrication System

Installation

1. Apply pipe sealant with Teﬂ on

(Loctite

PST

592™

Thread Sealant or equivalent) to threads of switch.

2. Install switch into tapped hole in breather cover.

3. Torque switch to 4.5 N·m (40 in. lb.).

Testing

Compressed air, a pressure regulator, pressure gauge,

and a continuity tester are required to test switch.

1. Connect continuity tester across blade terminal and

metal case of switch. With 0 psi pressure applied to

switch, tester should indicate continuity (switch

closed).

2. Gradually increase pressure to switch. As pressure

increases through range of 3-5 psi tester should

indicate a change to no continuity (switch open).

Switch should remain open as pressure is increased

to 90 psi maximum.

3. Gradually decrease pressure through range of 3-5

psi. Tester should indicate a change to continuity

(switch closed) down to 0 psi.

4. Replace switch if it does not operate as speciﬁ ed.

3324 690 07 Rev. L KohlerEngines.com

Electrical System

SPARK PLUGS

CAUTION

Electrical Shock can cause injury.

Do not touch wires while engine is running.

Spark Plug Component and Details

A Wire Gauge B Spark Plug

C Ground Electrode D Gap

NOTE: Do not clean spark plug in a machine using

abrasive grit. Some grit could remain in spark

plug and enter engine causing extensive wear

and damage.

Engine misﬁ re or starting problems are often caused

by a spark plug that has improper gap or is in poor

condition.

Engine is equipped with following spark plugs:

Gap 0.76 mm (0.030 in.)

Thread Size 14 mm

Reach 19.1 mm (3/4 in.)

Hex Size 15.9 mm (5/8 in.)

Refer to Maintenance for Repairs/Service Parts.

Service

Clean out spark plug recess. Remove plug and replace.

1. Check gap using wire feeler gauge. Adjust gap to

0.76 mm (0.030 in.).

2. Install plug into cylinder head.

3. Torque plug to 27 N·m (20 ft. lb.).

Inspection

Inspect each spark plug as it is removed from cylinder

head. Deposits on tip are an indication of general

condition of piston rings, valves, and carburetor.

Normal and fouled plugs are shown in following photos:

Normal

Plug taken from an engine operating under normal

conditions will have light tan or gray colored deposits. If

center electrode is not worn, plug can be set to proper

gap and reused.

Worn

On a worn plug, center electrode will be rounded and

gap will be greater than speciﬁ ed gap. Replace a worn

spark plug immediately.

Wet Fouled

A wet plug is caused by excess fuel or oil in combustion

chamber. Excess fuel could be caused by a restricted air

cleaner, a carburetor problem, or operating engine with

too much choke. Oil in combustion chamber is usually

caused by a restricted air cleaner, a breather problem,

worn piston rings, or valve guides.

Electrical System

34 24 690 07 Rev. LKohlerEngines.com

Carbon Fouled

Soft, sooty, black deposits indicate incomplete

combustion caused by a restricted air cleaner, over rich

carburetion, weak ignition, or poor compression.

Overheated

Chalky, white deposits indicate very high combustion

temperatures. This condition is usually accompanied

by excessive gap erosion. Lean carburetor settings,

an intake air leak, or incorrect spark timing are normal

causes for high combustion temperatures.

BATTERY

A 12-volt battery with 400 cold cranking amps (cca) is

generally recommended for starting in all conditions. A

smaller capacity battery is often suﬃ cient if an

application is started only in warmer temperatures. Refer

to following table for minimum capacities based on

anticipated ambient temperatures. Actual cold cranking

requirement depends on engine size, application, and

starting temperatures. Cranking requirements increase

as temperatures decrease and battery capacity shrinks.

Refer to equipment's operating instructions for speciﬁ c

battery requirements.

Battery Size Recommendations

Temperature Battery Required

Above 32°F (0°C) 200 cca minimum

0°F to 32°F (-18°C to 0°C) 250 cca minimum

-5°F to 0°F (-21°C to -18°C) 300 cca minimum

-10°F (-23°C) or below 400 cca minimum

If battery charge is insuﬃ cient to turn over engine,

recharge battery.

Battery Maintenance

Regular maintenance is necessary to prolong battery

life.

Battery Test

To test battery, follow manufacturer's instructions.

ELECTRONIC IGNITION SYSTEMS

Ignition System Components

Kill Switch/Oﬀ

Position of Key

Switch

B Air Gap

C Flywheel D Magnet

E Spark Plug F Ignition Modules

There are 3 diﬀ erent types of ignition systems used on

these engines. All systems use an ignition module which

energizes spark plug. Diﬀ erence in systems is in way

ignition timing is triggered.

All ignition systems are designed to be trouble free for

life of engine. Other than periodically checking/replacing

spark plugs, no maintenance or timing adjustments

are necessary or possible. Mechanical systems do

occasionally fail or break down. Refer to Troubleshooting

to determine root of a reported problem.

Reported ignition problems are most often due to poor

connections. Before beginning test procedure, check

all external wiring. Be certain all ignition-related wires

are connected, including spark plug leads. Be certain all

terminal connections ﬁ t snugly. Make sure ignition switch

is in run position.

3524 690 07 Rev. L KohlerEngines.com

Electrical System

Wiring Diagram-15/20/25 Amp Regulated Battery Charging System with Fixed Timing

Electrical System

36 24 690 07 Rev. LKohlerEngines.com

Fixed Ignition System

This system uses a capacitive discharge (CD) coil. Ignition timing and spark remains constant regardless of engine

speed. Timing of spark is controlled by location of ﬂ ywheel magnet group as referenced to engine TDC. A typical ﬁ xed

ignition system consists of:

● 1 magnet assembly which is permanently aﬃ xed to ﬂ ywheel.

● 2 electronic capacitive-discharge ignition modules which mount on engine crankcase.

● 1 kill switch (or key switch) which grounds modules to stop engine.

● 2 spark plugs.

A Spark Plug(s) B Oil Pressure Switch C Oil Sentry

(Green) D White Kill

Flywheel Stator

Assembly

F Ignition Module G

Non-Smart Spark

Ignition

Rectiﬁ er-Regulator

Connector

I Rectiﬁ er-Regulator J

Oil Sentry

Kill

(Green)

K Violet B+ L

Solenoid Shift Starter

Assembly

M Starter Solenoid Tang N Starter Solenoid Stud O Fuse P Blue

Alternate Ignition Kill

(–)

R White S Accessory Terminal (+) T Yellow

U Ignition Kill V Red W Carburetor X Carburetor Solenoid

Y Black (Ground) Z Intake Manifold Screw AA Black AB

Oil Sentry

Panel

Light/Remote Light

AC Oil Sentry

™

Light AD Connector AE Magneto AF Key Switch

AG Accessory AH Battery AI Starter AJ Ground

AK Key Switch Ground AL Rectiﬁ er AM Blue/Red AN Battery Positive

AO Battery Negative

3724 690 07 Rev. L KohlerEngines.com

Electrical System

Wiring Diagram-15/20/25 Amp Regulated Battery Charging System with Smart-Spark

Electrical System

38 24 690 07 Rev. LKohlerEngines.com

Smart-Spark

™

Advance Ignition System

SMART-SPARK

™

equipped engines utilize an electronic capacitive discharge ignition system with electronic spark

advance. A typical application consists of following components:

● 1 magnet assembly which is permanently aﬃ xed to ﬂ ywheel.

● 2 electronic capacitive discharge ignition modules which mount on engine crankcase.

● 1 spark advance module which mounts to engine shrouding.

● 1 12 volt battery which supplies current to spark advance module.

● 1 kill switch (or key switch) which grounds spark advance module to stop engine.

● 2 spark plugs.

A Oil Pressure Switch B Oil Sentry

™

(Green) C Spark Plug(s) D Kill

E Trigger F Ignition Module G

Flywheel Stator

Assembly

22, 25 HP Smart-

Spark

™

Ignition

Module Speed

Advance 22, 25 HP

J Brown K Yellow L

Yellow on Analog

SAMs Pink on Digital

SAMs

Rectiﬁ er-Regulator

Connector

N Rectiﬁ er-Regulator O

Oil Sentry™ Kill

(Green)

Solenoid Shift Starter

Assembly

Q Violet (B+) R

Alternate Ignition Kill

(–)

S Accessory Terminal (+) T White

U Ignition Kill V Smart-Spark

™

W Red X Carburetor

Y Solenoid Lead Z Intake Manifold Screw AA Black AB

Oil Sentry

™

Panel

Light/Remote Light

AC Oil Sentry

™

Light AD Connector AE Magneto AF Key Switch

AG Accessory AH Battery AI Starter AJ Ground

AK Key Switch Ground AL Rectiﬁ er AM Blue/Red AN Battery Positive

AO Battery Negative AP Blue AQ Fuse AR Starter Solenoid Stud

AS Starter Solenoid Tang AT Black (Ground)

3924 690 07 Rev. L KohlerEngines.com

Electrical System

Wiring Diagram-15/20/25 Amp Regulated Battery Charging System with DSAI Ignition and Key Switch

Electrical System

40 24 690 07 Rev. LKohlerEngines.com

DSAI Ignition System

This system uses a digital microprocessor which is located in ignition modules. Ignition timing varies depending upon

engine speed with this system. There are 2 inductive-style ignition modules that control ignition timing based on

engine RPM. A typical DSAI application consists of:

● 1 magnet assembly, which is permanently aﬃ xed to ﬂ ywheel.

● 2 inductive, 12-volt ignition modules, which mount on engine crankcase.

● 1 12-volt battery, which supplies current to ignition modules.

● 1 kill switch (or key switch) which grounds spark advance module to stop engine.

● 2 spark plugs.

A Oil Pressure Switch B

Green (Oil Sentry

Pulse Signal Lead)

Black (Ground)

Intake Manifold

Mounting Screw

D Black

E White F Red G Spark Plug(s) H Black (Ground)

I Red (B+) J White (DSAI Kill) K Module Screw L

Flywheel Stator

Assembly

M DSAI Module N

White

(AC Charging Leads)

Rectiﬁ er-Regulator

Connector

P Rectiﬁ er-Regulator

Q Violet (B+ Lead) R Starter Assembly S

Oil Sentry

Pulse

Signal

Alternate Ignition Pulse

Signal (–)

U Fuse V Starter Solenoid Tang W Starter Solenoid Stud X Blue

Y Accessory Terminal (+) Z Yellow AA Red (DSAI Power) AB White (DSAI Kill)

AC Carburetor AD Solenoid Lead AE Ground AF Intake Manifold Screw

AG Black (Ground) AH

Oil Sentry

Panel

Light/Remote Light

AI Oil Sentry

Light AJ Connector

AK Magneto AL Key Switch AM Accessory AN Battery

AO Starter AP

Key Switch Ground

(Black)

AQ Rectiﬁ er AR Blue/Red

AS Battery Positive AT Battery Negative AU

Customer Supplied

Relay Cranking

AV Relay Stud

4124 690 07 Rev. L KohlerEngines.com

Electrical System

Wiring Diagram-3 Amp Unregulated Battery Charging System/70 Watt Lighting

Optional Oil

Sentry

Switch

(Shutdown)

B 12 V. Battery C

Optional Oil

Sentry

Switch

(Indicator Light)

D Light E

Ground-To-Kill

Lead (White)

F Ground G

Optional

Ammeter

H Optional Fuse I Key Switch J Red

K Blue L Solenoid M Lights N Starter O Yellow

P Diode Q

3 Amp/70 Watt

Flywheel Stator

R Black S Spark Plug(s) T Ignition Modules

Electronic Ignition Systems Tests

NOTE: Ignition tester must be used to test ignition on these engines. Use of any other tester can result in inaccurate

ﬁ ndings. Battery on unit must be fully charged and properly connected before performing tests (a battery that

is hooked up or charged backward will crank engine but it won’t have spark). Be certain drive is in neutral and

all external loads are disconnected.

Test Ignition Systems

NOTE: If engine starts or runs during testing, you may need to ground kill lead to shut it down. Because you have

interrupted kill circuit, it may not stop using switch.

Isolate and verify trouble is within engine.

1. Locate connectors where wiring harnesses from engine and equipment are joined. Separate connectors and

remove white kill lead from engine connector. Rejoin connectors and position or insulate kill lead terminal so it

cannot touch ground. Try to start engine to verify whether reported problem is still present.

Condition Possible Cause Conclusion

Problem goes away. Electrical System Check key switch, wires, connections,

safety interlocks, etc.

Problem persists. Ignition or Electrical System Leave kill lead isolated until all testing

is completed.

Identify white kill lead of engine

wiring harness connector. Establish

a connection to a known good

ground location. Engine should kill

completely. If not or only one cylinder

is aﬀ ected, test ignition modules and

white kill lead connection for aﬀ ected

DSAI module (DSAI only).

Electrical System

42 24 690 07 Rev. LKohlerEngines.com

Test for Spark

NOTE: If 2 testers are available, testing can be performed simultaneously for both cylinders. However, if only 1 tester

is available, 2 individual tests must be performed. Side not being tested must have spark plug lead connected

or grounded. Do not crank engine or perform tests with 1 spark plug lead disconnected and not grounded, or

permanent system damage may occur.

1. With engine stopped, disconnect 1 spark plug lead. Connect spark plug lead to post terminal of spark tester and

attach tester clip to a good engine ground.

2. Crank engine over, establishing a minimum of 350-450 RPM, and observe tester(s) for spark.

3. Repeat spark test on opposite cylinder if cylinders are being tested individually.

Condition Possible Cause Conclusion

Both cylinders have good spark but

engine runs poorly or existing plug

condition is questionable.

Spark Plug(s) Install new spark plug(s) and retest

engine performance.

If problem persists, check for timing

advance (DSAI and Smart-Spark

only).

1 cylinder has good spark and other

cylinder has no or intermittent spark.

Ignition Test ignition modules and

connections (DSAI and Smart-Spark

™

only).

Spark on both cylinders but power is

suspect.

Timing Advance Check for timing advance (DSAI and

Smart-Spark

™

only).

Test Timing Advance (DSAI and Smart-Spark

™

only)

1. Make a line near edge of ﬂ ywheel screen with a marking pen, chalk, or narrow tape.

2. Connect an automotive timing light to cylinder that had good spark.

3. Run engine at idle and use timing light beam to locate line on screen. Draw a line on blower housing next to line

on screen. Accelerate to full throttle and watch for movement of line on screen relative to line on blower housing. If

both cylinders had good spark, repeat test on other cylinder.

Condition Possible Cause Conclusion

Line on screen did not move away

from line on blower housing during

acceleration.

Ignition Test ignition modules and

connections.

Lines made on blower housing not

90° apart.

Test Ignition Modules and Connections (DSAI only)

1. Remove blower housing from engine. Inspect wiring for any damage, cuts, bad crimps, loose terminals, or broken

wires. Check that connections are oriented properly on terminals of modules.

2. Disconnect leads from ignition module(s) and clean all of terminals (male and female) with aerosol electrical

contact cleaner to remove any old dielectric compound, dark residue, dirt, or contamination. Disconnect spark

plug leads from spark plugs.

3. Using a multi-meter, check that a proper ground is established between ground (black) lead of DSAI module

(closest to spark plug lead) and a known good ground location on engine.

4. Turn key switch to ON position and check for 12 volts at center/power (red) lead terminal of DSAI module. Use

same ground location for multi-meter as in checking for timing advance.

Condition Possible Cause Conclusion

All tests are OK but module has no

spark or fails to advance.

Ignition Module Replace aﬀ ected module.

Any test is BAD. Ignition Module or Connections Determine cause and ﬁ x as required;

retest.

4324 690 07 Rev. L KohlerEngines.com

Electrical System

Test Ignition Modules and Connections (Smart-

Spark

™

only)

NOTE: Resistance values apply only to modules that

have been on a running engine. New service

modules may have higher resistance until they

have been run.

1. Remove blower housing from engine. Inspect wiring

for any damage, cuts, bad crimps, loose terminals,

or broken wires.

2. Disconnect leads from ignition module(s) and clean

all of terminals (male and female) with aerosol

electrical contact cleaner to remove any old

dielectric compound, dark residue, dirt, or

contamination. Disconnect spark plug leads from

spark plugs.

3. Remove one mounting screw from each ignition

module. If mounting screws are black, remove them

both and discard. Look in mounting hole with a

ﬂ ashlight and use a small round wire brush to

remove any loose rust from laminations inside

mounting hole.

4. Use a digital ohmmeter to check resistance values

and compare them to ignition module resistance

table. When testing resistance to laminations, touch

probe to laminations inside screw hole, as some

laminations have a rust preventative coating on

surface which could alter resistance reading.

Condition Possible Cause Conclusion

All resistance values are within

ranges speciﬁ ed in table.

Ignition Module Gap Check and adjust ignition module

gap.

At least 1 resistance value is not

within ranges speciﬁ ed in table.

Ignition Module Ignition module is faulty and should

be replaced.

24 584 03

24 584 11

(1 11/16 in. High)

24 584 15-S

24 584 36-S

(2 1/16 in. High)

Test

(Use Digital

Ohmmeter)

From No.

1 to 4

From No.

2 to 4

From No.

3 to 4

24 584 03

24 584 11

(1 11/16 in. H)

945 to

1175 ohms

149 to

166 ohms

3750 to

7000 ohms

24 584 15-S

(2 1/16 in. H)

890 to

1175 ohms

119 to

136 ohms

5600 to

9000 ohms

24 584 36-S

(2 1/16 in. H)

590 to

616 ohms

183 to

208 ohms

8000 to

40,000 ohms

Ignition Module Resistance Table

5. Check and/or adjust ignition module air gap(s). An air gap of 0.28/0.33 mm (0.011/0.013 in.) must be maintained

under all three legs of ignition module(s). Checking/adjusting should be performed with parts at room temperature.

Condition Possible Cause Conclusion

Module was not loosened or

replaced.

Ignition Module Air Gap Check that speciﬁ ed air gap is

present under all three legs. If gap is

correct, reinstall second mounting

screw removed earlier and recheck

gap after tightening.

Module was loosened or replaced. Ignition Module Adjust ignition module air gap.

a. Adjust ignition module air gap.

1. Turn ﬂ ywheel magnet away from module position.

2. Attach module to mounting legs, pull it away from ﬂ ywheel, and tighten screws to hold it temporarily.

3. Rotate ﬂ ywheel so magnet is centered under module.

4. Position a 0.30 mm (0.012 in.) feeler gauge between magnet and all three legs of module. Ignition module

air gap is critical to proper system performance. Do not attempt to set it with a business card or folded

microﬁ che card. Use feeler gauge speciﬁ ed.

5. Loosen mounting screws, allow magnet to pull module down against feeler gauge, and retighten mounting

screws.

6. Rotate ﬂ ywheel to remove feeler gauge, position magnet back under module, and recheck that speciﬁ ed

gap, minimum of 0.28 mm (0.011 in.), exists under each leg of module. When you are certain gap is correct,

torque module mounting screws to 4.0 N·m (35 in. lb.). Repeat these 6 steps to set other ignition module.

6. Reattach lead wires to ignition module(s), noting if resistance is felt, indicating a snug ﬁ t between male and female

terminals. If any connections do not feel snug, disconnect lead, lightly pinch female terminal with a pliers, and

recheck ﬁ t.

7. When integrity of all connections has been veriﬁ ed, retest for spark.

Electrical System

44 24 690 07 Rev. LKohlerEngines.com

Condition Possible Cause Conclusion

Strong, steady spark is now present

on both sides.

SAM Problem should be corrected. Go to

Test SAM step 4.

Still a spark problem. SAM Test SAM.

Test SAM

1. Trace red power source lead from SAM to harness connection. Separate connector and connect red lead of a DC

voltmeter to harness terminal. Trace ground lead from SAM (black on singles, green on twins) to grounding screw.

Connect black voltmeter lead to eyelet terminal of ground lead or ground screw/bolt. Check voltage with key

switch in both START and RUN positions. A minimum of 7.25 volts must be present.

a. If correct voltage is not measured, connect black voltmeter lead directly to negative (–) post of battery and test

voltage again in both key positions. If correct voltage is now indicated, check ground circuit connections. If

ground screw/bolt or any other fasteners in ground circuit are black (oxide-coated), replace them with zinc

plated (silver colored) fasteners.

b. If correct voltage is still not indicated, check harness connector terminal for a good connection and crimp to

lead. Then trace power source circuit back through harness, key switch, etc., looking for any poor connections,

or faulty circuits.

Condition Possible Cause Conclusion

Incorrect voltage is measured. Voltage Connect black voltmeter lead directly

to negative (–) post of battery and test

voltage again in both key positions.

If correct voltage is still not indicated,

check harness connector terminal for

a good connection and crimp to lead.

Then trace power source circuit back

through harness, key switch, etc.,

looking for any poor connections, or

faulty circuits.

Correct voltage is measured. Voltage Check ground circuit connections.

If ground screw/bolt or any other

fasteners in ground circuit are black

(oxide-coated), replace them with zinc

plated (silver colored) fasteners.

2. Disconnect all SAM leads, isolating it from engine. Test SAM according to style with tester 25 761 21-S (tests

ASAM style modules only), or tester 25 761 40-S (tests both ASAM and DSAM style modules). Use test

instructions following, or those provided with tester. If SAM tests bad, replace it.

3. Reattach SAM leads, verifying a snug ﬁ t at ignition module terminals. If any connections do not feel snug,

disconnect lead, lightly pinch female terminal with a pliers, and recheck ﬁ t.

4. Seal base of ignition module connections with GE/Novaguard G661 or equivalent dielectric compound. Beads

should overlap between two connections to form a solid bridge of compound. Do not put any compound inside

connectors.

24 584 15-S ignition modules have a separator/barrier between terminals. On these modules, seal base of

terminal if any portion of it is exposed, but it is not necessary to have overlapping beads of sealant between

connections.

5. Test for spark to be sure system is working, before you reinstall blower housing. If there is still a spark problem on

one side, replace that ignition module and recheck spark.

Test ASAM and DSAM

Allow 15-20 seconds for tester to clear and reset itself between tests or if test is interrupted before completion of test

cycle. Otherwise, a false reading may be displayed in form of a (–) or a faint 8.

Tester is powered by a 9-volt battery. Most SAMs are designed to operate down to a minimum of 7.25 volts. If tester

battery drops below that level, incorrect test readings will result. Tester battery should be checked periodically by

connecting a DC voltmeter between red and green lead wires, with tester connected to a SAM. Press and hold test

button for a full test cycle (F or P appears and then display shuts oﬀ ), while monitoring voltage reading on voltmeter.

If voltage drops below 7.5 at any time during cycle, 9-volt tester battery must be replaced. Use an extended life

(alkaline) battery.

To replace battery, remove outer set of screws on faceplate and carefully lift panel from body. Unplug connector and

pull battery (with mounting tape) oﬀ back of tester. Attach connector to new battery and mount battery to case with

double-backed tape. Reinstall faceplate and secure with four screws.

4524 690 07 Rev. L KohlerEngines.com

Electrical System

To test ASAM only using 25 761 21-S tester:

NOTE: SAM must be at room temperature when tested.

Disconnect all SAM leads, isolating it from main

wiring harness and ignition module(s). Testing

may be performed with module mounted or

loose.

NOTE: Do not allow alligator clip leads to touch each

other.

1. Connect tester to SAM by attaching:

a. Yellow tester lead to long yellow module lead.

b. Brown tester lead to long brown module lead.

c. Red tester lead to red module lead.

d. Green tester lead to green module lead.

2. Check SAM part number stamped on side of

housing. Verify that you have an analog SAM

(ASAM) Part No. 24 584 10 or lower, not a digital

SAM (DSAM) Part No. 24 584 18 and higher. Follow

sub-step a for testing an ASAM with this tester.

Digital SAM (DSAM) modules require Tester 25 761

40-S for proper testing.

a. Depress tester button and hold it down. After

approximately four seconds, a numerical

sequence should be displayed, beginning with 1

or 2 and continuing to 8 or 9, followed by a letter

P (pass) or F (fail). Do not release tester button

until test cycle completes and display goes oﬀ . If

you get a (–) sign instead of numerical sequence,

and/or an F at end of cycle, SAM is probably bad.

Recheck all connections, check condition of

tester battery and repeat test. If you get (–) sign

and/or F again in retest, replace that SAM.

3. Disconnect yellow and brown tester leads from long

module leads. Connect brown tester lead to short

brown module lead. Connect yellow tester lead to

short yellow (or pink) module lead. Leave red and

green leads connected. Repeat step 2.

To test DSAM and ASAM using 25 761 40-S tester:

NOTE: Do not allow alligator clip leads to touch each

other.

NOTE: SAM must be at room temperature when tested.

Disconnect all SAM leads, isolating it from main

wiring harness and ignition module(s). Testing

may be performed with module mounted or

loose.

NOTE: Some modules contain two black ground leads,

with one containing a white stripe. Do not

connect to black/white lead with bullet connector

or a Fail test result will occur, regardless of

actual condition.

Test procedure for twin cylinder SAMs will vary slightly,

depending on whether module is analog (ASAM) or

digital (DSAM).

1. Check SAM part number stamped on end of

housing.

a. If it is an ASAM (24 584 09 or 24 584 10),

separate short yellow and brown leads from long

ones. Each set will be tested separately. Connect

tester to SAM as follows:

● Yellow tester lead to long yellow module lead.

● Brown tester lead to long brown module lead.

● Red tester lead to red module lead.

● Black tester lead to black or green module lead.

Remaining tester leads (pink and brown with black

band) are not used for testing ASAMs.

b. If it is a DSAM (all except 24 584 09 or 24 584

10), connect tester as follows:

● Yellow tester lead to long yellow module lead.

● Brown tester lead to long brown module lead.

● Red tester lead to red module lead.

● Black tester lead to green or black module ground

lead with eyelet terminal.

● Pink tester lead to short yellow or pink module

lead.

● Brown tester lead with black band or terminal to

short brown module lead.

2. Recheck SAM part number, noting last two digits.

Refer to table below or on tester faceplate to

determine test number to be used.

SAM Part

No.

24 584 18

24 584 27

24 584 19

24 584 38

24 584 39

Test No. 5678

SAM Part

No.

12 584 12

24 584 09

24 584 10

24 584 30

24 584 31

24 584 33

24 584 34

24 584 32

Test No. 1234

3. Depress tester button repeatedly until correct test

number appears on display. After a few seconds,

test number will ﬂ ash three times and test will begin.

A reverse numerical sequence will be displayed,

starting with a 6 and progressing down to 1, followed

by a P (pass) or F (fail), indicating condition of part.

If testing an ASAM, return to step 1 and move yellow

and brown tester leads to short set of module leads,

then repeat test.

4. If you get a (–) sign instead of numerical sequence,

and/or an F at end of test cycle, recheck all

connections, check condition of tester battery and

repeat test. If you get (–) or F sign again in retest

replace SAM.

BATTERY CHARGING SYSTEM

NOTE: Observe following guidelines to avoid damage to

electrical system and components:

● Make sure battery polarity is correct. A negative (–)

ground system is used.

● Disconnect rectiﬁ er-regulator plug and/or wiring

harness plug before doing any electric welding on

equipment powered by engine. Disconnect all other

electrical accessories in common ground with engine.

● Prevent stator (AC) leads from touching or shorting

while engine is running. This could damage stator.

Most engines are equipped with a 15 or 20 amp

regulated charging system. Some have a 25 amp

regulated charging system. Some engines utilize a 3

amp unregulated system with optional 70 watt lighting

circuit.

Electrical System

46 24 690 07 Rev. LKohlerEngines.com

15/20/25 Amp Regulated Charging System

Stator

Stator is mounted on crankcase behind ﬂ ywheel. Follow procedures in Disassembly and Reassembly if stator

replacement is necessary.

Rectiﬁ er-Regulator

NOTE: When installing rectiﬁ er-regulator, take note of terminal markings and install plug(s) accordingly.

NOTE: Disconnect all electrical connections attached to rectiﬁ er-regulator. Testing may be performed with rectiﬁ er-

regulator mounted or loose. Repeat applicable test procedure 2 or 3 times to determine condition of part.

Rectiﬁ er-regulator is mounted on blower housing. To replace it, disconnect plug(s), remove mounting screws, and

ground wire or metal grounding strap.

Testing of rectiﬁ er-regulator may be performed as follows, using appropriate Rectiﬁ er-Regulator Tester.

To test 4/15 amp rectiﬁ er-regulators:

1. Connect tester ground lead (with spring clamp) to

body of rectiﬁ er-regulator being tested.

2. Connect tester red lead to B+ terminal of rectiﬁ er-

regulator and 2 black tester leads to 2 AC terminals.

3. Plug tester into proper AC outlet/power for tester

being used. Turn on power switch. POWER light

should be illuminated and 1 of 4 status lights may be

on as well. This does not represent condition of part.

4. 4 amp: Press TEST button until a click is heard and

then release. Momentarily either HIGH, LOW, or

SHORT light will ﬂ ash.

15 amp: Press TEST button until a click is heard and

then release. Momentarily 1 of 4 status lights will

illuminate, indicating condition of part.

To test 20/25 amp rectiﬁ er-regulators:

1. 20 amp: Connect single lead adapter in between B+

(center) terminal of rectiﬁ er-regulator being tested

and squared single end of tandem adapter lead.

25 amp: Connect squared single end of tandem lead

adapter to B+ (center/red) lead of rectiﬁ er-regulator

being tested.

2. Connect tester ground lead (with spring clamp) to

body of rectiﬁ er-regulator.

3. Connect red lead and 1 black lead to pair of

terminals on open end of tandem adapter lead

(connections are not location speciﬁ c).

4. Connect remaining black lead from tester to 1 outer

AC terminal on rectiﬁ er-regulator.

5. Plug tester into proper AC outlet/power for tester

being used. Turn on power switch. POWER light

should be illuminated and 1 of 4 status lights may be

on as well. This does not represent condition of part.

6. Press TEST button until a click is heard and then

release. Momentarily 1 of 4 status lights will

illuminate indicating partial condition of part.

Condition Conclusion

4 amp 15 Amp 20 amp 25 amp

OK (green) or HIGH light comes on

and stays steady.

Part is good and may be used. Disconnect tester black lead attached

to 1 AC terminal and reconnect it to

other AC terminal. Repeat test. If OK

(green) light comes on again, part is

good and may be used.

NOTE: A ﬂ ashing LOW light can

also occur as a result of an

inadequate ground lead

connection. Make certain

connection location is clean

and clamp is secure.

Other lights come on.

Rectiﬁ er-regulator is faulty and should not be used.

4724 690 07 Rev. L KohlerEngines.com

Electrical System

15/20/25 Amp Battery Charging Systems

NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should be

made with engine running at 3600 RPM with no load. Battery must be good and fully charged.

When problems occur in keeping battery charged or battery charges at high rate, charging system or battery might be

causing problems.

To test charging system for no charge to battery:

1. Insert an ammeter in B+ lead from rectiﬁ er-regulator.

With engine running at 3600 RPM and B+ (at

terminal on rectiﬁ er-regulator) to ground using a DC

voltmeter.

If voltage is 13.8 volts or more, place a minimum

load of 5 amps (turn on lights if 60 watts or more, or

place a 2.5 ohm, 100 watt resistor across battery

terminals) on battery to reduce voltage. Observe

ammeter.

Condition Conclusion

Charge rate increases

when load is applied.

Charging system is OK

and battery was fully

charged.

Charge rate does not

increase when load is

applied.

Test stator and rectiﬁ er-

regulator (steps 2 and 3).

2. Remove connector from rectiﬁ er-regulator. With

engine running at 3600 RPM, measure AC voltage

across stator leads using an AC voltmeter.

Condition Conclusion

Voltage is 28 volts or

more.

Stator is OK. Rectiﬁ er-

regulator is faulty; replace.

Voltage is less than 28

volts.

Stator is faulty; replace.

Test stator further using an

ohmmeter (steps 3 and 4).

3. With engine stopped, measure resistance across

stator leads using an ohmmeter.

Condition Conclusion

Resistance is 0.1/0.2

ohms.

Stator is OK.

Resistance is 0 ohms. Stator is shorted; replace.

Resistance is inﬁ nity

ohms.

Stator is open; replace.

4. With engine stopped, measure resistance from each

stator lead to ground using an ohmmeter.

Condition Conclusion

Resistance is inﬁ nity ohms

(no continuity).

Stator is OK (not shorted

to ground).

Resistance (or continuity)

measured.

Stator leads are shorted to

ground; replace.

To test charging system for battery continuously charging

at high rate:

1. With engine running at 3600 RPM, measure voltage

from B+ lead to ground using a DC voltmeter.

Condition Conclusion

Voltage is 14.7 volts or

less.

Charging system is OK.

Battery is unable to hold

charge; service or replace.

Voltage is more than 14.7

volts.

Faulty rectiﬁ er-regulator;

replace.

Electrical System

48 24 690 07 Rev. LKohlerEngines.com

3 Amp/70 Watt Lighting Stator

NOTE: Zero ohm meteres on each scale to ensure

accurate readings. Voltage tests should be made

with engine running at 3000 RPM with no load.

Battery must be good and fully charged.

To test charging system for no charge to battery:

1. With engine running in fast setting, measure voltage

across battery terminals using a DC voltmeter.

Condition Conclusion

Voltage is more than 12.5

volts.

Charging system is OK

Voltage is 12.5 volts or

less.

Stator or diode are

probably faulty. Continue

testing stator and diode.

2. Remove connector from rectiﬁ er-regulator. With

engine running in fast position, measure AC voltage

across stator leads using an AC voltmeter.

Condition Conclusion

Voltage is 28 volts or

more.

Stator winding is OK.

Voltage is less than 28

volts.

Test stator using an

ohmmeter.

3. With charging lead disconnected from battery and

engine stopped, measure resistance from charging

lead to ground using an ohmmeter. Note reading.

Reverse leads and measure resistance again.

In one direction, resistance should be inﬁ nity ohms

(open circuit). With leads reversed, some resistance

should be measured (about midscale on Rx1 range).

Condition Conclusion

Resistance is low in both

directions.

Diode is shorted. Replace

diode.

Resistance is high in both

directions.

Diode or stator winding is

open. Continue testing.

4. Cut sleeving on charging lead to expose diode

connections.

Measure resistance from stator side of diode to

ground using an ohmmeter.

Condition Conclusion

Resistance is

approximately 1.07 ohms.

Stator winding is OK,

diode is open. Replace

diode.

Resistance is 0 ohms. Stator winding is shorted.

Replace stator.

Resistance is inﬁ nity

ohms.

Stator winding or lead is

open. Replace stator.

To test charging system for no lights:

1. Make sure lights are not burned out.

Condition Conclusion

Burned out lights. Replace.

2. Disconnect lighting lead from wiring harness.

With engine running in fast setting, measure voltage

from lighting lead to ground using an AC voltmeter.

Condition Conclusion

Voltage is 15 volts or

more.

Stator is OK. Check for

loose connections or

shorts in wiring harness.

Voltage is less than 15

volts.

Test stator using an

ohmmeter.

3. With engine stopped, measure resistance of stator

from lighting lead to ground using an ohmmeter.

Condition Conclusion

Resistance is

approximately 0.4 ohms.

Stator is OK.

Resistance is 0 ohms. Stator is shorted. Replace

stator.

Resistance is inﬁ nity

ohms.

Stator or lighting lead is

open. Replace stator.

Starter System

24 690 07 Rev. L

KohlerEngines.com 49

NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool down period between

starting attempts. Failure to follow these guidelines can burn out starter motor.

NOTE: If engine develops suﬃ cient speed to disengage starter but does not keep running (a false start), engine

rotation must be allowed to come to a complete stop before attempting to restart engine. If starter is engaged

while ﬂ ywheel is rotating, starter pinion and ﬂ ywheel ring gear may clash and damage starter.

NOTE: If starter does not crank engine, shut oﬀ starter immediately. Do not make further attempts to start engine until

condition is corrected.

NOTE: Do not drop starter or strike starter frame. Doing so can damage starter.

Engines in this series use inertia drive, solenoid shift, or retractable starters.

Troubleshooting-Starting Diﬃ culties

Condition Possible Cause Conclusion

Starter does not energize. Battery Check speciﬁ c gravity of battery. If low, recharge or replace

battery as necessary.

Wiring Clean corroded connections and tighten loose connections.

Replace wires in poor condition and with frayed or broken

insulation.

Starter Switch

or Solenoid

By-pass switch or solenoid with a jumper wire. If starter cranks

normally, replace faulty components. Remove and perform

individual solenoid test procedure.

Starter energizes but turns

slowly.

Battery Check speciﬁ c gravity of battery. If low, recharge or replace

battery as necessary.

Brushes Check for excessively dirty or worn brushes and commutator.

Clean using a coarse cloth (not emery cloth).

Replace brushes if excessively or unevenly worn.

Transmission

Engine

Make sure clutch or transmission is disengaged or placed

in neutral. This is especially important on equipment with

hydrostatic drive. Transmission must be exactly in neutral to

prevent resistance which could keep engine from starting.

Check for seized engine components such as bearings,

connecting rod, and piston.

Starter System

24 690 07 Rev. L

KohlerEngines.com

INERTIA DRIVE ELECTRIC STARTERS

Inertia Drive Starter Components

Style A

Style B

Style A

Style B

A Dust Cover B Stop Nut

C Stop Gear Spacer D Anti-Drift Spring

E Dust Cover Spacer F Drive Pinion

G Retaining Ring H Spring Retainer

I Drive Nut (Collar)

When power is applied to starter, armature rotates. As

armature rotates, drive pinion moves out on drive shaft

splines and into mesh with ﬂ ywheel ring gear. When

pinion reaches end of drive shaft, it rotates ﬂ ywheel and

cranks engine.

When engine starts, ﬂ ywheel rotates faster than starter

armature and drive pinion. This moves drive pinion out

of mesh with ring gear and into retracted position. When

power is removed from starter, armature stops rotating

and drive pinion is held in retracted position by anti-drift

spring.

Starter Drive Service

Style A

NOTE: Do not over-tighten vise as this can distort drive

pinion.

1. Remove starter from engine and remove dust cover.

2. Hold drive pinion in a vice with soft jaws when

removing or installing stop nut. Armature will rotate

with nut until drive pinion stops against internal

spacers.

3. Remove stop nut, stop gear spacer, anti-drift spring,

dust cover spacer, and drive pinion.

4. Clean splines on drive shaft thoroughly with solvent.

Dry splines thoroughly.

5. Apply a small amount of Kohler electric starter drive

lubricant, to splines. Use of other lubricants may

cause drive pinion to stick or bind.

6. Apply a small amount of Loctite

271™ to stop nut

threads.

7. Install drive pinion, dust cover spacer, anti-drift

spring, stop gear spacer, and stop nut. Torque stop

nut to 17.0-19.2 N·m (150-170 in. lb.). Reinstall dust

cover.

Style B

1. Rubber dust cover has a molded lip on inside that

snaps into a groove in dust cover spacer Turn drive

pinion clockwise until it reaches fully extended

position. While holding it in extended position, grasp

tip of dust cover with a pliers or vise grip and pull it

free from spacer.

2. Disassemble snap ring removal tool.

3. Grasp spring retainer and push it toward starter,

compressing anti-drift spring and exposing retaining

ring.

4. Holding spring retainer in retracted position,

assemble inner halves of removal tool around

armature shaft with retaining ring in inner groove.

Slide collar over inner halves to hold them in

position.

5. Thread center screw into removal tool until you feel

resistance. Use a wrench (1-1/8 or adjustable) to

hold base of removal tool. Use another wrench or

socket (1/2 or 13 mm) to turn center screw

clockwise. Resistance against center screw will tell

you when retaining ring has popped out of groove in

armature shaft.

6. Remove drive components from armature shaft,

paying attention to sequence. If splines are dirty,

clean them with solvent.

7. Splines should have a light ﬁ lm of lubricant.

Relubricate as necessary with Kohler starter drive

lubricant. Reinstall or replace drive components,

assembling them in reverse order they were

removed.

Starter System

24 690 07 Rev. L

KohlerEngines.com 51

Retaining Ring Installation

1. Position retaining ring in groove in one of inner

halves. Assemble other half over top and slide on

outer collar.

2. Be certain drive components are installed in correct

sequence onto armature shaft.

3. Slip tool over end of armature shaft, so retaining ring

inside is resting on end of shaft. Hold tool with one

hand, exerting slight pressure toward starter. Tap top

of tool with a hammer until you feel retaining ring

snap into groove. Disassemble and remove tool.

4. Squeeze retaining ring with a pliers to compress it

into groove.

5. Assemble inner halves with larger cavity around

spring retainer. Slide collar over them and thread

center screw in until resistance is felt.

6. Hold base of tool with a 1-1/8 wrench and turn

center screw clockwise with a 1/2 or 13 mm wrench

to draw spring retainer up around retaining ring. Stop

turning when resistance increases. Disassemble and

remove tool.

7. Reinstall dust cover.

Starter Disassembly

1. Remove drive components following instructions for

servicing drive.

2. Locate small raised line on edge of drive end cap.

On starters with style A commutator end caps, it will

be aligned with a pre-marked line on starter frame.

Frame is not pre-marked on starters with style B end

caps. Place a piece of masking tape on frame and

mark a line on tape in line with raised line on end

cap.

3. Remove thru bolts.

4. Remove commutator end cap with brushes and

brush springs (style A). Style B end caps remove as

a separate piece with brushes and carrier remaining

in frame.

5. Remove drive end cap.

6. Remove armature and thrust washer (if equipped)

from inside starter frame.

7. Remove brush/carrier assembly from frame (style B

starters).

Brush Replacement

Style A

NOTE: Use a brush holder tool to keep brushes in

pockets. A brush holder tool can easily be made

from thin sheet metal.

1. Remove brush springs from pockets in brush holder.

2. Remove self-tapping screws, negative (–) brushes,

and plastic brush holder.

3. Remove nut and ﬁ ber washer from stud terminal.

Remove stud terminal with positive (+) brushes and

plastic insulating bushing from end cap.

4. Install insulating bushing on stud terminal of new

positive (+) brushes. Install stud terminal into

commutator end cap. Secure stud with ﬁ ber washer

and screw.

5. Install brush holder, new negative (–) brushes, and

self-tapping screws.

6. Install brush springs and brushes into pockets in

brush holder. Make sure chamfered sides of brushes

are away from brush springs.

Style B

Starters with style B end caps have brushes in a plastic

carrier housing, separate from end cap. Replacement

brushes come preassembled in carrier housing, retained

with two carton staples.

Commutator Service

Clean commutator with a coarse, lint free cloth. Do not

use emery cloth.

If commutator is badly worn or grooved, turn it down on

a lathe or replace starter.

Starter Reassembly

1. Place thrust washer (if equipped) over drive shaft of

armature.

2. Insert armature into starter frame. Make sure

magnets are closer to drive shaft end of armature.

Magnets will hold armature inside frame.

3. Install drive end cap over drive shaft. Make sure

match marks on end cap and starter frame are

aligned.

4. Style A commutator end caps:

Install brush holder tool to keep brushes in pockets

of commutator end cap.

Align match marks on commutator end cap and

starter frame. Hold drive end and commutator end

caps ﬁ rmly to starter frame. Remove brush holder

tool.

Style B commutator end caps:

If brush assembly is not being replaced, position

brushes in their pockets in carrier. Move them to

retracted position, and install carton staples to retain

them.

Align terminal stud block with notch in starter frame

and slide brush/carrier assembly into frame.

Commutator will push carton staples out as brush

assembly is installed. Position end cap over brush

assembly, so holes for thru bolts are aligned with

those in brush carrier.

5. Install thru bolts and tighten securely.

6. Lubricate drive shaft with Kohler starter drive

lubricant. Install drive components following

instructions for servicing starter drive.

Starter System

24 690 07 Rev. L

KohlerEngines.com

SOLENOID SHIFT ELECTRIC STARTERS

Solenoid Shift Starter Components

A Tube B Washer

C Armature D Drive

E Stop F Retaining Ring

G Collar H Drive End Cap

I Screw J Plunger

K Spring L Lever

M Plate N Plug

O Solenoid P Frame and Field

Q Brush Holder R Nut

Commutator End

Plate

T Screw

U Bolt

When power is applied to starter electric solenoid moves

drive pinion out onto drive shaft and into mesh with

ﬂ ywheel ring gear. When pinion reaches end of drive

shaft it rotates ﬂ ywheel and cranks engine.

When engine starts and start switch is released, starter

solenoid is deactivated, drive lever moves back, and

drive pinion moves out of mesh with ring gear into

retracted position.

Nippondenso Starters

Starter Disassembly

NOTE: When removing lever and armature be careful

not to lose thrust washer.

1. Disconnect lead wire from solenoid.

2. Remove nuts securing solenoid, and remove

solenoid from starter assembly.

3. Remove two thru bolts.

4. Remove commutator end cap.

5. Remove insulator and brush springs from brush

spring holder.

6. Remove armature from frame.

7. Remove drive lever and armature from drive end

cap.

8. Stop collar consists of two similar pieces held in

place by being snapped over a retainer. Retainer is

held in place by a groove in armature shaft. To

remove stop collar two pieces must be pried oﬀ

retainer.

9. When stop collars are removed retainer can be

removed from armature shaft. Do not reuse retainer.

Brush Replacement

Brushes in starter are part of starter frame. Brush kit

contains four replacement brushes and springs. If

replacement is necessary, all four brushes should be

replaced.

1. Remove brushes from brush holder, and remove

brush holder from frame.

2. Cut brush lead wire at edge of post with a pair of

nippers.

3. File oﬀ any burrs on post.

4. Replacement brushes have a solid portion which

should be crimped on post.

5. Solder crimped portion to post.

6. Replace brush holder in frame and place brushes in

brush holder. Reinstall springs.

Starter Reassembly

NOTE: Always use a new retainer. Tighten retainer in

groove to secure.

1. Insert rear stop collar on armature shaft.

2. Place retainer in groove on armature shaft.

3. Fit front stop collar over shaft and bring front and

rear stop collars together over retainer. Using two

pairs of pliers apply even force to two collars until

they snap over retainer and nest into one another.

4. Reassemble remaining components of starter in

reverse order from disassembly.

Delco-Remy Starters

Starter Disassembly

NOTE: Do not reuse old retainer.

NOTE: Do not soak armature or use solvent when

cleaning. Wipe clean using a soft cloth, or use

compressed air.

Starter System

24 690 07 Rev. L

KohlerEngines.com 53

1. Remove hex nut and disconnect positive (+) brush

lead/bracket from solenoid terminal.

2. Remove head screws securing solenoid to starter.

3. If solenoid was mounted with Phillips head screws,

separate solenoid and plunger spring from drive end

cap. If solenoid was mounted with external Torx

head screws, plunger is part of solenoid, unhook

plunger pin from drive lever. Remove gasket from

recess in housing.

4. Remove thru (larger) bolts.

5. Remove commutator end plate assembly, containing

brush holder, brushes, springs, and locking caps.

Remove thrust washer from inside commutator end.

6. Remove frame from armature and drive end cap.

7. Remove drive lever pivot bushing and backing plate

from end cap.

8. Take out drive lever and pull armature out of drive

end cap.

9. Remove thrust washer from armature shaft.

10. Push stop collar down to expose retaining ring.

11. Remove retainer from armature shaft. Save stop

collar.

12. Remove drive pinion assembly from armature.

13. Clean parts as required.

Inspection

Drive Pinion

Check and inspect following areas:

● Pinion teeth for abnormal wear or damage.

● Surface between pinion and clutch mechanism for

nicks or irregularities which could cause seal damage.

● Check drive clutch by holding clutch housing and

rotating pinion. Pinion should rotate in only 1 direction.

Brushes and Springs

Detail

A Wear Limit Length

Inspect both springs and brushes for wear, fatigue, or

damage. Measure length of each brush. Minimum length

for each brush is 7.6 mm (0.300 in.). Replace brushes if

they are worn, undersize, or condition is questionable.

Armature

Components and Details

A Commutator O.D. B Mica Insulation

C Insulation Check D Armature Coil

E Continuity Check

1. Clean and inspect commutator (outer surface). Mica

insulation must be lower than commutator bars

(undercut) to ensure proper operation of

commutator.

2. Use an ohmmeter set to Rx1 scale. Touch probes

between 2 diﬀ erent segments of commutator, and

check for continuity. Test all segments. Continuity

must exist between all or armature is bad.

3. Check for continuity between armature coil

segments and commutator segments. There should

be no continuity. If continuity exists between any 2

armature is bad.

4. Check armature windings/insulation for shorting.

Shift Fork

Check that shift fork is complete, and pivot and contact

areas are not excessively worn, cracked, or broken.

Brush Replacement

4 brushes and springs are serviced as a set. Use a new

Kohler brush and spring kit if replacement is necessary.

1. Perform steps 1-5 in Starter Disassembly.

2. Remove screws securing brush holder assembly to

end cap (plate). Note orientation for reassembly

later. Discard old brush holder assembly.

3. Clean component parts as required.

4. New brushes and springs come preassembled in a

brush holder with a protective sleeve that will also

serve as an installation tool.

5. Perform Steps 10-13 in Starter Reassembly

sequence. Installation must be done after armature,

drive lever, and frame are installed, if starter has

been disassembled.

Starter System

24 690 07 Rev. L

KohlerEngines.com

Starter Reassembly

NOTE: Always use a new retainer. Do not reuse old

retainers that have been removed.

NOTE: Correctly installed, center pivot section of drive

lever will be ﬂ ush or below machined surface of

housing.

1. Apply drive lubricant to armature shaft splines. Install

drive pinion onto armature shaft.

2. Install and assemble stop collar/retainer assembly.

a. Install stop collar down onto armature shaft with

counter bore (recess) up.

b. Install a new retainer in larger (rear) groove of

armature shaft. Squeeze with a pliers to

compress it in groove.

c. Slide stop collar up and lock it into place, so

recess surrounds retainer in groove. If necessary,

rotate pinion outward on armature splines against

retainer to help seat collar around retainer.

3. Install oﬀ set thrust (stop) washer so smaller oﬀ set of

washer faces retainer/collar.

4. Apply a small amount of oil to bearing in drive end

cap, and install armature with drive pinion.

5. Lubricate fork end and center pivot of drive lever

with drive lubricant. Position fork end into space

between captured washer and rear of pinion.

6. Slide armature into drive end cap and at same time

seat drive lever into housing.

7. Install backup washer, followed by rubber grommet,

into matching recess of drive end cap. Molded

recesses in grommet should be out, matching and

aligned with those in end cap.

8. Install frame, with small notch forward, onto

armature and drive end cap. Align notch with

corresponding section in rubber grommet. Install

drain tube in rear cutout, if it was removed

previously.

9. Install ﬂ at thrust washer onto commutator end of

armature shaft.

10. Starter reassembly when replacing brushes/brush

holder assembly:

a. Hold starter assembly vertically on end housing,

and carefully position assembled brush holder

assembly, with supplied protective tube, against

end of commutator/armature. Mounting screw

holes in metal clips must be up/out. Slide brush

holder assembly down into place around

commutator, and install positive (+) brush lead

grommet in cutout of frame. Protective tube may

be saved and used for future servicing.

Starter reassembly when not replacing brushes/

brush holder assembly:

a. Carefully unhook retaining caps from brush

assemblies. Do not lose springs.

b. Position brushes back in their slots so they are

ﬂ ush with I.D. of brush holder assembly. Insert

brush installation tool (with extension), or use

tube described above from a prior brush

installation, through brush holder assembly, so

holes in metal mounting clips are up/out.

c. Install brush springs and snap on retainer caps.

d. Hold starter assembly vertically on end housing,

and carefully place tool (with extension) and

assembled original brush holder assembly onto

end of armature shaft. Slide brush holder

assembly down into place around commutator,

install positive (+) brush lead grommet in cutout

of frame.

11. Install end cap onto armature and frame, aligning

thin raised rib in end cap with corresponding slot in

grommet of positive (+) brush lead.

12. Install thru bolts and brush holder mounting screws.

Torque bolts to 5.6-9.0 N·m (49-79 in. lb.) and brush

holder mounting screws to 2.5-3.3 N·m

(22-29 in. lb.).

13. Hook plunger behind upper end of drive lever and

install spring into solenoid. Insert mounting screws

through holes in drive end cap. Use these to hold

solenoid gasket in position, then mount solenoid.

Torque screws to 4.0-6.0 N·m (35-53 in. lb.).

14. Connect positive (+) brush lead/bracket to solenoid

and secure with nut. Torque nut to 8-11 N·m

(71-97 in. lb.). Do not overtighten.

Starter System

24 690 07 Rev. L

KohlerEngines.com 55

Solenoid Tests

NOTE: DO NOT leave 12 volt test leads connected to solenoid for any time over what is necessary for performing

each of individual tests. Internal damage to solenoid may occur.

Disconnect all leads from solenoid including positive brush lead attached to lower stud terminal. Remove mounting

hardware and separate solenoid from starter for testing.

To test solenoid pull-in coil/plunger:

Actuation

1. Use a 12 volt power supply and 2 test leads.

2. Connect 1 lead to ﬂ at spade S/start terminal on

solenoid. Momentarily connect other lead to lower

large post terminal.

When connection is made solenoid should energize

(audible click) and plunger retract. Repeat test

several times.

Continuity

1. Use an ohmmeter set to audible or Rx2K scale, and

connect 2 ohmmeter leads to 2 large post terminals.

2. Perform solenoid pull-in coil/plunger actuation test

and check for continuity. Ohmmeter should indicate

continuity. Repeat test several times.

To test solenoid hold-in coil:

Function

1. Connect a 12 volt test lead to ﬂ at spade S/start

terminal on solenoid and other lead to body or

mounting surface of solenoid.

2. Manually push plunger IN and check if coil holds

plunger retracted. Do not allow test leads to remain

connected to solenoid for a prolonged period of time.

Continuity

1. Use an ohmmeter set to audible or Rx2K scale, and

connect 2 ohmmeter leads to 2 large post terminals.

2. Perform preceding solenoid hold-in coil function test

and check for continuity. Meter should indicate

continuity. Repeat test several times.

Condition Conclusion

Solenoid fails to activate. Replace solenoid.

No continuity is indicated.

Plunger fails to stay retracted.

Starter System

24 690 07 Rev. L

KohlerEngines.com

RETRACTABLE STARTERS

WARNING

Uncoiling Spring can cause severe injury.

Wear safety goggles or face protection when

servicing retractable starter.

Retractable starters contain a powerful, recoil spring

that is under tension. Always wear safety goggles

when servicing retractable starters and carefully follow

instructions in Retractable Starter for relieving spring

tension.

Retractable Starter Components

A Hex Flange Screws B Starter Housing

Handle with Rope

Retainer

D Rope

E Spring and Keeper F Pulley

G Pawl Springs H Pawls

I Brake Washer J Brake Spring

K Pawl Retainer L Plain Washer

M Center Screw N Drive Cup

Remove Starter

1. Remove screws securing starter to blower housing.

2. Remove starter assembly.

Rope Replacement

NOTE: Do not allow pulley/spring to unwind. Enlist aid

of a helper if necessary.

Rope can be replaced without complete starter

disassembly.

1. Remove starter assembly from engine.

2. Pull rope out approximately 12 in. and tie a

temporary (slip) knot in it to keep it from retracting

into starter.

3. Pull knot end out of handle, untie knot, and slide

handle oﬀ .

4. Hold pulley ﬁ rmly and untie slipknot. Allow pulley to

rotate slowly as spring tension is released.

5. When all spring tension on starter pulley is released,

remove rope from pulley.

6. Tie a double left-hand knot in one end of new rope.

7. Rotate pulley counterclockwise (when viewed from

pawl side of pulley) until spring is tight

(approximately 6 full turns of pulley).

8. Continue rotating pulley counterclockwise until rope

hole in pulley is aligned with rope guide bushing of

starter housing.

9. Insert unknotted end of new rope through rope hole

in starter pulley and rope guide bushing of housing.

10. Tie a slipknot approximately 12 in. from free end of

rope. Hold pulley ﬁ rmly and allow it to rotate slowly

until slipknot reaches guide bushing of housing.

11. Insert starter rope through starter handle and tie a

double, left-hand knot at end of starter rope. Insert

knot into hole in handle.

12. Untie slip knot and pull on starter handle until starter

rope is fully extended. Slowly retract starter rope into

starter assembly. If recoil spring is properly

tensioned, starter rope will retract fully and starter

handle will stop against starter housing.

Starter System

24 690 07 Rev. L

KohlerEngines.com 57

Pawls (dogs) Replacement

1. Install a clamp to hold pulley in starter housing and

prevent if from rotating.

2. Remove center screw, washer, and pawl retainer.

3. Note position of pawls and pawl springs before

removing. Remove pawls, pawls springs, brake

spring and brake washer from pulley.

4. Clean/wipe out center pocket of pulley to remove

any accumulated dirt and old lubricant.

5. Apply small amount of grease to new brake washer

and spring, install them in center pocket.

6. Install pawl springs and pawls into pawl slots of

pulley. All parts must be dry.

7. Position drive plate over pawls with actuating ears

down and inside of pawls.

8. Apply a small amount of Loctite

271™ to threads of

center screw. Install center screw with washer.

Torque screw to 7.4-8.5 N·m (65-75 in. lb.).

9. Remove clamp and pull starter rope out part way to

check operation of pawls.

Install Starter

1. Install retractable starter onto blower housing leaving

screws slightly loose.

2. Pull starter handle out until pawls engage in drive

cup. Hold handle in this position and tighten screws

securely.

WARNING

Before working on engine or equipment, disable engine as

follows: 1) Disconnect spark plug lead(s). 2) Disconnect

negative (–) battery cable from battery.

Accidental Starts can cause severe injury or

death.

Disconnect and ground spark plug lead(s)

before servicing.

External Engine Components

A Guard B Blower Housing C Fuel Filter D Rectiﬁ er-Regulator

E Outer Baﬄ e F Electric Starter G Inner Baﬄ e H Fuel Pump

I Hose J Oil Cooler K O-ring L Nipple

M Oil Filter

Disassembly/Inspection and Service

58 24 690 07 Rev. LKohlerEngines.com

Clean all parts thoroughly as engine is disassembled.

Only clean parts can be accurately inspected

and gauged for wear or damage. There are many

commercially available cleaners that will quickly remove

grease, oil, and grime from engine parts. When such a

cleaner is used, follow manufacturer’s instructions and

safety precautions carefully.

Make sure all traces of cleaner are removed before

engine is reassembled and placed into operation. Even

small amounts of these cleaners can quickly break down

lubricating properties of engine oil.

Disconnect Spark Plug Leads

NOTE: Pull on boot only, to prevent damage to spark

plug lead.

1. Disconnect leads from spark plugs.

2. Shut oﬀ fuel supply.

Drain Oil From Crankcase and Remove Oil Filter

1. Remove oil ﬁ ll cap/dipstick and 1 oil drain plug.

2. Allow ample time for oil to drain from crankcase and

oil ﬁ lter.

3. Remove mounting screw and detach oil ﬁ ll tube.

4. Remove and discard oil ﬁ lter.

Remove Oil Cooler (if equipped)

1. Use a 5/16" Allen wrench to remove oil ﬁ lter nipple.

2. For crankcase-mounted cooler: Separate oil cooler

from oil pan. Remove and discard gasket located

between them.

For blower housing-mounted cooler: Separate ﬁ lter

adapter from oil pan, leaving oil lines attached.

Remove screws mounting oil cooler to blower

housing. Remove cooler, lines, and ﬁ lter adapter as

an assembly.

Remove Muﬄ er

Remove exhaust system and attaching hardware from

engine. On engines equipped with a port liner, remove it

now.

Remove Air Cleaner Assembly

Low-Proﬁ le and Commercial Mower Air Cleaners

1. Unhook latches located on either side of air cleaner

cover, or loosen cover-retaining knob, and remove

cover.

2. Remove wing nut from element cover.

3. Remove element cover, element and precleaner.

4. Remove nuts securing spitback cup, baﬄ e or

bracket, and air cleaner base. Additional lower

screws must be removed if engine contains a lower

air cleaner support bracket.

5. Disconnect breather tube from nipple on underside,

or hose from base (as equipped).

6. Remove base and gasket while carefully pulling

rubber breather tube through base.

Heavy-Duty Air Cleaner

1. Disconnect breather hose from ﬁ tting in adapter or

elbow. Remove nuts securing adapter and any

attached clips to mounting studs.

2. Pull adapter elbow and gasket oﬀ mounting studs.

3. Remove screws (inner valve cover screws on each

side) securing air cleaner main support bracket. Do

not lose any of mounting hardware.

Two-barrel carburetor models only: unhook choke

return spring from bottom of air cleaner mounting

bracket.

4. Remove upper screws securing air cleaner mounting

bracket to blower housing and remove air cleaner

assembly.

Remove Control Panel (if equipped)

1. Disconnect Oil Sentry

™

Indicator Light wires.

2. Disconnect choke control cable from throttle control

bracket.

3. Disconnect throttle control bracket from cylinder

head.

4. Remove panel from blower housing.

Remove Fuel Pump

WARNING

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings,

away from sparks or ﬂ ames. Spilled fuel could ignite

if it comes in contact with hot parts or sparks from

ignition. Never use gasoline as a cleaning agent.

1. Disconnect fuel lines at carburetor and at in-line fuel

ﬁ lter.

2. Disconnect pulse (vacuum) hose from crankcase.

3. Remove mounting screws from blower housing and

remove fuel pump and lines as an assembly.

Disassembly/Inspection and Service

5924 690 07 Rev. L KohlerEngines.com

Remove Throttle Controls

Control Panel Components

A Nut B Lock Nut

C Flat Washer D Control Bracket

E Carburetor F Air Cleaner Gasket

G Governor Lever H Governor Spring

I Throttle Shaft J Bracket

K Spacer L

Throttle Control

Lever

M Linkage Spring N Throttle Linkage

O Carburetor Gasket P Choke Linkage

Q Choke Lever R Screw

S Throttle Shaft Spring

1. Remove screws securing throttle control bracket and

lower air cleaner bracket (some models), to cylinder

heads.

2. Disconnect spring from governor lever; note hole

locations for reassembly.

3. Remove choke linkage from choke actuator lever

and carburetor.

Remove External Governor Controls

Loosen nut and remove governor lever from cross shaft.

Leave lever attached to throttle linkage.

Remove Carburetor

WARNING

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings,

away from sparks or ﬂ ames. Spilled fuel could ignite if it

comes in contact with hot parts or sparks from ignition.

Never use gasoline as a cleaning agent.

1. Disconnect fuel shut-oﬀ solenoid lead if equipped.

2. Remove carburetor mounting nuts.

3. Remove carburetor, throttle linkage and governor

lever as an assembly.

4. Remove carburetor gasket.

5. If necessary, carburetor, throttle linkage and

governor lever can be separated. Reattach bushings

to linkage following separation to avoid losing them.

Remove Electric Starter Motor

1. Disconnect leads from starter.

2. Remove screws.

3. Remove starter assembly and lift bracket. Some

inertia drive starters use a separate starter cover

and spacers.

Remove Outer Baﬄ es and Blower Housing

1. Disconnect wire leads from start switch on blower

housing (if equipped). Disconnect plug from rectiﬁ er-

regulator. Use tip of dipstick or a similar small ﬂ at

tool to bend locking tang, then remove B+ terminal

from center position in plug. This will allow blower

housing to be removed without disturbing wiring

harness.

2. Rectiﬁ er-regulator does not have to be detached

from blower housing. If engine is equipped with

SMART-SPARK

™

, remove mounting screws from

spark advance module (SAM). Module will hang

loose as part of wiring harness.

3. Remove screws securing outer baﬄ es. Note location

of any lifting strap and position of short screws (one

each side on bottom) for reassembly.

4. Remove outer baﬄ es.

5. If ﬂ ywheel screen overlaps blower housing, remove

fasteners and screen. If it was a metal screen with

long bolts, also remove remaining loose hardware

and cooling fan.

6. Remove remaining screws securing blower housing.

Note 1 silver plated screw used for rectiﬁ er-regulator

ground strap or lead. Remove blower housing.

Disassembly/Inspection and Service

60 24 690 07 Rev. LKohlerEngines.com

Remove Valve Covers

Three valve cover designs have been used. First type

used a gasket and RTV sealant between cover and

sealing surface of cylinder head. Second type had a

black O-ring installed in a groove on underside of cover

and may have metal spacers in bolt holes. Latest design

uses a yellow or brown O-ring, and bolt hole spacers are

molded in place.

1. Remove screws securing each valve cover. Note

valve cover diﬀ erences for proper location in

reassembly.

2. O-ring type covers should lift oﬀ without prying. If

loose spacers are present, save them. With gasket

type, break seal by carefully prying under edges of

cover.

Remove Ignition Modules

1. Disconnect lead(s) from each ignition module.

2. Rotate ﬂ ywheel so magnet is away from modules.

3. Remove mounting screws and ignition modules.

Note position of ignition modules.

Remove Spark Plugs

Remove spark plug from each cylinder head.

Remove Oil Sentry

™

1. Disconnect lead from Oil Sentry

™

switch.

2. Remove Oil Sentry

™

switch from breather cover.

Remove Inner Baﬄ es and Breather Cover

1. Remove screws securing inner baﬄ es to crankcase.

2. Remove inner (valley) baﬄ es.

3. Remove remaining screws from breather cover.

4. Pry under protruding edge of breather cover with a

screwdriver to break RTV or gasket seal. Do not pry

on sealing surfaces as it could cause damage

resulting in leaks. Most engines use a formed gasket

rather than RTV sealant.

5. Remove breather cover and gasket (if used).

Crankcase Breather System

Breather system is designed to control amount of oil

in head area and still maintain necessary vacuum in

crankcase.

A spring steel reed and stop is mounted on each bank

of crankcase, between lifter bores. When pistons move

downward, air is pushed past reeds into cylinder head

cavities. On cylinder 2, upper end of head is completely

sealed by rocker cover, so a low, positive pressure is

created in head cavity. Cylinder 1 rocker cover has

a hole in it for venting. Bottom nipple of oil separator

canister is ﬁ tted into hole with a grommet. From top

nipple of canister, a breather hose goes back to air

cleaner base. Air moving into cylinder 1 head cavity is

ﬁ ltered through oil separator and then is drawn into air

intake.

Upward travel of pistons closes reeds and creates

a low vacuum in lower crankcase. A combination of

low pressure above and low vacuum below forces

any accumulated oil out of cylinder 2 head area into

crankcase. On cylinder 1 bank you have atmospheric

pressure above and vacuum below, again drawing any

oil toward crankcase.

Disassembly/Inspection and Service

6124 690 07 Rev. L KohlerEngines.com

Cylinder Head Components

A Valves B Cylinder Head C Spark Plug D Nut

E Hydraulic Lifter F Cap G Valve Stem Seal H Valve Spring Keeper

I Valve Spring J

Valve Spring

Retainer

K Rocker Arm Pivot L Push Rod

M Rocker Arm N Screw O Valve Cover O-ring P Grommet

Q Valve Cover R Gasket

Remove Cylinder Heads and Hydraulic Lifters

NOTE: Cylinder heads are retained using either screws or nuts and washers on studs. Do not interchange or mix

components, as cylinder heads may have diﬀ erent machining, unique to each fastening method.

1. Remove screws or nuts and washers securing each cylinder head. Unless screws are damaged or questionable,

they can be reused. Discard nuts and washers once removed; do not reuse. Studs (if present) should only be

removed if damaged or if cylinder reconditioning is necessary. Once removed, they must be replaced.

2. Mark location of push rods as either intake or exhaust and cylinder 1 or 2. Push rods should always be reinstalled

in same positions.

3. Carefully remove push rods, cylinder heads, and head gaskets.

4. Remove lifters from lifter bores. Use a hydraulic lifter tool. Do not use a magnet to remove lifters. Mark lifters by

location, as either intake or exhaust, and cylinder 1 or 2. Hydraulic lifters should always be reinstalled in same

position.

Disassembly/Inspection and Service

62 24 690 07 Rev. LKohlerEngines.com

Disassemble Cylinder Heads

NOTE: These engines use valve stem seals on intake valves. Use a new seal whenever valve is removed or if seal is

deteriorated or damaged in any way. Never reuse an old seal.

1. Remove screws, rocker arm pivots and rocker arms from cylinder head. Note screw color for reassembly.

2. Compress valve springs using a valve spring compressor.

3. Once valve spring is compressed, remove following items.

● Valve spring keepers.

● Valve spring retainers.

● Valve springs.

● Valve spring caps.

● Intake and exhaust valves (mark position).

● Valve stem seal (intake valve only).

4. Repeat above procedure for other cylinder head. Do not interchange parts from 1 cylinder head to other.

Inspection and Service

Valve Details

EXHAUST VALVE INTAKE VALVE

EXHAUST

INSERT

INTAKE

INSERT

B A

Dimension Intake Exhaust

A Seat Angle 89° 89°

B Insert O.D. 36.987/37.013 mm (1.4562/1.4572 in.) 32.987/33.013 mm (1.2987/1.2997 in.)

C Guide Depth 4 mm (0.1575 in.) 6.5 mm (0.2559 in.)

D Guide I.D. 7.038/7.058 mm (0.2771/0.2779 in.) 7.038/7.058 mm (0.2771/0.2779 in.)

E Valve Head Diameter 33.37/33.63 mm (1.3138/1.3240 in.) 29.37/29.63 mm (1.1563/1.1665 in.)

F Valve Face Angle 45° 45°

G Valve Margin (Min.) 1.5 mm (0.0591 in.) 1.5 mm (0.0591 in.)

H Valve Stem Diameter 6.982/7.000 mm (0.2749/0.2756 in.) 6.970/6.988 mm (0.2744/0.2751 in.)

After cleaning, check ﬂ atness of cylinder head and

corresponding top surface of crankcase, using a surface

plate or precision straight edge and feeler gauge.

Maximum allowable out of ﬂ atness is:

0.076 mm (0.003 in.) for 73, 77, and 80 mm bores;

0.1 mm (0.004 in.) for 83 mm bore.

Carefully inspect valve mechanism parts. Inspect valve

springs and related hardware for excessive wear or

distortion. Check valves and valve seat area or inserts

for evidence of deep pitting, cracks, or distortion. Check

clearance of valve stems in guides.

Hard starting, or loss of power accompanied by high

fuel consumption may be symptoms of faulty valves.

Although these symptoms could also be attributed to

worn rings, remove and check valves ﬁ rst. After removal,

clean valve heads, faces, and stems with a power wire

brush.

Disassembly/Inspection and Service

6324 690 07 Rev. L KohlerEngines.com

Lapping Valves

NOTE: Exhaust valves that are black in color cannot be

ground and do not require lapping.

Reground or new valves must be lapped in, to provide

proper ﬁ t. Use a hand valve grinder with a suction cup

for ﬁ nal lapping. Lightly coat valve face with a ﬁ ne grade

of grinding compound, then rotate valve on its seat with

grinder. Continue grinding until a smooth surface is

obtained on seat and on valve face. Thoroughly clean

cylinder head in soap and hot water to remove all traces

of grinding compound. After drying cylinder head, apply

a light coating of SAE 10 oil to prevent rusting.

Intake Valve Stem Seal

These engines use valve stem seals on intake valves.

Always use a new seal when valves are removed

from cylinder head. Seals should also be replaced if

deteriorated or damaged in any way. Never reuse an old

seal.

Hydraulic Lifters Inspection

Check base surface of hydraulic lifters for wear or

damage. If lifters need to be replaced, apply a liberal

coating of Kohler lubricant to base of each new lifter

before it is installed.

Bleeding Lifters

To prevent a possible bent push rod or broken rocker

arm, it is important to bleed any excess oil out of lifters

before they are installed.

1. Cut a 50-75 mm (2-3 in.) piece from end of an old

push rod and chuck it in a drill press.

2. Lay a rag or shop towel on table of drill press and

place lifter, open end up, on towel.

3. Lower chucked push rod until it contacts plunger in

lifter. Slowly pump plunger 2 or 3 times to force oil

out of feed hole in side of lifter.

Then, carefully inspect each valve for defects such as

warped head, excessive corrosion, or worn stem end.

Replace valves found to be in bad condition.

Valve Guides

If a valve guide is worn beyond speciﬁ cations, it will not

guide valve in a straight line. This may result in burnt

valve faces or seats, loss of compression, and excessive

oil consumption.

To check valve guide-to-valve stem clearance,

thoroughly clean valve guide and, using a split-ball

gauge, measure inside diameter of guide. Then, using

an outside micrometer, measure diameter of valve stem

at several points on stem where it moves in valve guide.

Use largest stem diameter to calculate clearance by

subtracting stem diameter from guide diameter. If intake

clearance exceeds 0.038/0.076 mm (0.0015/0.0030

in.) or exhaust clearance exceeds 0.050/0.088 mm

(0.0020/0.0035 in.), determine whether valve stem or

guide is responsible for excessive clearance.

Maximum (I.D.) wear on intake valve guide is 7.134 mm

(0.2809 in.) while 7.159 mm (0.2819 in.) is maximum

allowed on exhaust guide. Guides are not removable but

can be reamed 0.25 mm (0.010 in.) oversize. Valves with

0.25 mm oversize stems must then be used.

If guides are within limits but valve stems are worn

beyond limits, install new valves.

Valve Seat Inserts

Hardened steel alloy intake and exhaust valve seat

inserts are press-ﬁ tted into cylinder head. Inserts are

not replaceable but can be reconditioned if not too badly

pitted or distorted. If cracked or badly warped, cylinder

head should be replaced.

Recondition valve seat inserts following instructions

provided with valve seat cutter being used. Final cut

should be made with an 89° cutter as speciﬁ ed for

valve seat angle. Cutting proper 45° valve face angle,

as speciﬁ ed, and proper valve seat angle (44.5°, half of

full 89° angle), will achieve desired 0.5° (1.0° full cut)

interference angle where maximum pressure occurs on

outside diameters of valve face and seat.

Disassembly/Inspection and Service

64 24 690 07 Rev. LKohlerEngines.com

Flywheel/Ignition Components

A Flywheel Screw B Debris Screen

C Support Ring D Fan

E Magnet F Stator

G Ignition Module H Stud

I Screw J Woodruﬀ Key

K Manifold L Backing Plate

M Flywheel N Washer

Remove Intake Manifold

1. Remove screws securing intake manifold to cylinder

heads. Note which screws hold wiring clamps.

2. Remove intake manifold and intake manifold gaskets

(aluminum intake manifolds) or O-ring (plastic intake

manifolds).

3. Leave wiring harness attached to manifold.

Remove Debris Screen and Fan

1. On engines with a ﬂ at plastic screen, small metal

retainers are typically attached on 3 of 7 mounting

posts for positive retention of plastic debris screen.

Use a hook-end tool next to post and pull outward to

separate each of small metal retainers. Then unsnap

screen from mounting posts.

2. Remove screws or studs and washers. Remove

plastic fan from ﬂ ywheel.

Remove Flywheel

NOTE: Always use a ﬂ ywheel strap wrench or holding

tool to hold ﬂ ywheel when loosening or

tightening ﬂ ywheel screw. Do not use any type

of bar or wedge to hold ﬂ ywheel. Use of such

tools could cause ﬂ ywheel to become cracked or

damaged.

NOTE: Always use a ﬂ ywheel puller to remove ﬂ ywheel

from crankshaft. Do not strike crankshaft or

ﬂ ywheel, as these parts could become cracked

or damaged. Striking puller or crankshaft can

cause crank gear to move, aﬀ ecting crankshaft

endplay.

1. Use a ﬂ ywheel strap wrench or holding tool to hold

ﬂ ywheel and loosen screw securing ﬂ ywheel to

crankshaft.

2. Remove screw and washer.

3. Use a puller to remove ﬂ ywheel from crankshaft.

4. Remove woodruﬀ key.

Inspection

Inspect ﬂ ywheel for cracks, and ﬂ ywheel keyway for

damage. Replace ﬂ ywheel if it is cracked. Replace

ﬂ ywheel, crankshaft, and key if ﬂ ywheel key is sheared

or keyway is damaged.

Inspect ring gear for cracks or damage. Kohler does

not provide ring gears as a serviceable part. Replace

ﬂ ywheel if ring gear is damaged.

Remove Stator and Backing Plates

1. Remove screws securing backing plates and stator

wire bracket (if equipped). Remove backing plates

and stator wire bracket.

2. Remove screws and stator. Note position/routing of

stator lead.

Disassembly/Inspection and Service

6524 690 07 Rev. L KohlerEngines.com

Breather/Oil Pan/Oil Reservoir/Piston Components

A Oil Fill/Dipstick B Dipstick Tube C Oil Seal D Breather Gasket

E Breather Cover F Flat Washer G Breather Reed H Governor Cross Shaft

I Oil Pan Gasket J Governor Gear K

Locking Tab Thrust

Washer

L Oil Screen (Style A)

M Gerotor Gear (Style A) N

Oil Pick-Up Tube

(Style A)

Oil Pump Assembly

(Style A)

P Piston Pin

Q Piston (Style A) R Piston Ring Set S Piston Ring Retainer T

Connecting Rod End

Cap

U Connecting Rod V Crankshaft W Camshaft X Piston (Style B)

Y Oil Pan (Style A) Z Oil Pan (Style B) AA

Oil Pump Assembly

(Style B)

Outer Gerotor Gear

(Style B)

Oil Pump Cover O-ring

(Style B)

AD Spring (Style B) AE Ball (Style B) AF Oil Screen (Style B)

Disassembly/Inspection and Service

66 24 690 07 Rev. LKohlerEngines.com

Remove Oil Pan Assembly

1. Remove screws securing oil pan to crankcase.

2. Locate splitting tabs cast into perimeter of oil pan.

Insert drive end of a 1/2" breaker bar between

splitting tab and crankcase and turn it to break RTV

seal. Do not pry on sealing surfaces as this can

cause leaks.

Inspection

Inspect oil seal in oil pan and remove it if it is worn

or damaged. Refer to Install Oil Seal in Oil Pan in

Reassembly for new oil seal installation.

Inspect main bearing surface for wear or damage (refer

to Speciﬁ cations). Replace oil pan assembly if required.

Governor Gear Assembly

Governor Shaft Component and Details

34.0 mm (1.3386 in.)

33.5 mm (1.3189 in.)

B 19.40 mm (0.7638 in.)

C Gear Shaft

Governor gear assembly is located inside oil pan. If

service is required, refer to Inspection, Disassembly, and

Reassembly procedures.

Inspection

Inspect governor gear teeth. Replace gear if it is worn,

chipped, or if any teeth are missing. Inspect governor

weights. They should move freely in governor gear.

Disassembly

NOTE: Governor gear is held onto shaft by small

molded tabs in gear. When gear is removed from

shaft, these tabs are destroyed and gear must

be replaced. Therefore, remove gear only if

absolutely necessary.

Governor gear must be replaced once it is removed from

oil pan.

1. Remove regulating pin and governor gear assembly.

2. Remove locking tab thrust washer located under

governor gear assembly.

3. Carefully inspect governor gear shaft and replace it

only if it is damaged. After removing damaged shaft,

press or lightly tap replacement shaft into oil pan to

depth shown.

Reassembly

1. Install locking tab thrust washer on governor gear

shaft with tab down.

2. Position regulating pin within governor gear/ﬂ yweight

assembly and slide both onto governor shaft.

Disassembly/Inspection and Service

6724 690 07 Rev. L KohlerEngines.com

Reassembly

1. Install pressure relief valve piston and spring.

2. Install oil pickup to oil pump body. Lubricate O-ring

with oil and make sure it remains in groove as

pickup is being installed.

3. Install rotor.

4. Install oil pump body to oil pan and secure with

screws. Torque screws as follows:

a. Install fastener into screw location 1 and lightly

tighten to position pump.

b. Install fastener into screw location 2 and fully

torque to recommended value.

c. Torque fastener in screw location 1 to

recommended value.

First Time Installation: 10.7 N·m (95 in. lb.)

All Reinstallations: 6.7 N·m (60 in. lb.)

5. After torquing, rotate gear and check for freedom of

movement. Make sure there is no binding. If binding

occurs, loosen screws, reposition pump, retorque

screws and recheck movement.

Oil Pump Assembly (Style A)

Oil Pump

(Original Style A)

Oil Pump

(Later Style A)

C Oil Pickup Tube D Roll Pin

E Piston F Spring G O-Ring H Plastic Oil Pickup

One-Piece Relief

Valve

Torque Sequence

(Style A)

Oil Pump Assembly (Style A)

Oil pump is mounted inside oil pan. If service is required,

continue with Disassembly, Inspection, and Reassembly.

Disassembly

1. Remove screws.

2. Remove oil pump assembly from oil pan.

3. Remove oil pump rotor. If a plastic pickup is used,

unhook locking clip, and carefully pull it free from oil

pump housing.

4. If relief valve is like that shown, drive out pin to

remove oil pressure relief valve piston and spring.

Refer to following inspection and reassembly

procedures.

If relief valve is a one-piece style, staked to oil pump

housing, removal should not be attempted, nor is

internal servicing possible. If a problem with relief

valve is encountered, oil pump should be replaced.

Inspection

Inspect oil pump housing, gear, and rotors for nicks,

burrs, wear, or any visible damage. If any parts are worn

or damaged, replace oil pump.

Inspect oil pressure relief valve piston. It should be free

of nicks or burrs.

Check spring for wear or distortion. Free length of spring

should be approximately 47.4 mm (1.8 in.). Replace

spring if it is distorted or worn.

Disassembly/Inspection and Service

68 24 690 07 Rev. LKohlerEngines.com

Oil Pump Assembly (Style B)

Oil pump is mounted inside oil pan. If service is required,

continue with Disassembly, Inspection, and Reassembly.

Disassembly

1. Remove screws.

2. Lift oil pump assembly from oil pan. Remove outer

gerotor gear from oil pan.

3. Ensure ball and spring remain installed in pressure

relief hole of oil pan. If ball and spring fall out of

pressure relief hole, see reassembly for correct

installation.

4. Remove oil pump cover O-ring from groove in oil

pan.

Inspection

Inspect oil pump housing, gear, and rotors for nicks,

burrs, wear, or any visible damage. Inspect oil pump

cover O-ring for cuts, nicks, or any visible damage. If any

parts are worn or damaged, replace oil pump assembly

and/or O-ring. Check oil pickup screen for damage or

restriction, replace if necessary.

Reassembly

1. Lubricate outer gerotor gear with oil. Install outer

gerotor gear through shaft of oil pump, around inner

gerotor gear. Matching molding dots on inner and

outer gerotor gears is not necessary and will not

aﬀ ect oil pump eﬃ ciency.

2. Reinstall ball, then spring into pressure relief hole in

oil pan.

3. Reinstall O-ring into groove in oil pan; make sure it is

fully seated in groove.

4. Install oil pump inserting center shaft into

corresponding recess in oil pan. Apply consistent

downward pressure to oil pump cover, compressing

oil pressure relief spring and start screws. Secure oil

pump by torquing screws (in no speciﬁ c sequence)

to 9.0 N·m (80 in. lb.).

5. After torquing, rotate gear and check for freedom of

movement. Make sure there is no binding. If binding

occurs, loosen screws, reposition pump, retorque

screws and recheck movement.

Remove Camshaft

Remove camshaft and shim (if used).

Inspection and Service

NOTE: To prevent repeat failures, camshaft and

crankshaft should always be replaced as a set.

Check lobes of camshaft for wear or damage. See

Speciﬁ cations for minimum lift tolerance. Inspect

cam gear for badly worn, chipped or missing teeth.

Replacement of camshaft will be necessary if any of

these conditions exist.

Remove Governor Cross Shaft

1. Remove hitch pin and plain washer, or retainer and

nylon washer, from governor cross shaft.

2. Remove cross shaft through inside of crankcase.

Governor Cross Shaft Oil Seal

A B

A 2.0 mm (0.0787 in.)

B Governor Cross Shaft Seal

If governor cross shaft seal is damaged and/or leaks,

replace it using following procedure.

Remove oil seal from crankcase and replace it with a

new one. Install new seal to depth shown using a seal

installer.

Remove Connecting Rods with Pistons and Rings

NOTE: If a carbon ridge is present at top of either

cylinder bore, use a ridge reamer tool to remove

it before attempting to remove piston.

NOTE: Cylinders are numbered on crankcase. Use

numbers to mark each end cap, connecting rod

and piston for reassembly. Do not mix end caps

and connecting rods.

1. Remove screws securing closest connecting rod end

cap. Remove end cap.

2. Carefully remove connecting rod and piston

assembly from cylinder bore.

3. Repeat above procedure for other connecting rod

and piston assembly.

Disassembly/Inspection and Service

6924 690 07 Rev. L KohlerEngines.com

Piston and Rings

Inspection

Piston and Rings Components and Details

Style A

Style B

A Piston B

Middle Compression

Ring

Top Compression

Ring

D Rails

E Expander F

Oil Control Ring

(3 Piece)

NOTE: Rings must be installed correctly. Ring

installation instructions are usually included with

new ring sets. Follow instructions carefully. Use

a piston ring expander to install rings. Install

bottom (oil control) ring ﬁ rst and top

compression ring last.

Scuﬃ ng and scoring of pistons and cylinder walls occurs

when internal engine temperatures approach welding

point of piston. Temperatures high enough to do this are

created by friction, which is usually attributed to improper

lubrication and/or overheating of engine.

Normally, very little wear takes place in piston boss-

piston pin area. If original piston and connecting rod can

be reused after new rings are installed, original pin can

also be reused but new piston pin retainers are required.

Piston pin is included as part of piston assembly – if pin

boss in piston or pin are worn or damaged, a new piston

assembly is required.

Ring failure is usually indicated by excessive oil

consumption and blue exhaust smoke. When rings fail,

oil is allowed to enter combustion chamber where it is

burned along with fuel. High oil consumption can also

occur when piston ring end gap is incorrect because

ring cannot properly conform to cylinder wall under this

condition. Oil control is also lost when ring gaps are not

staggered during installation.

When cylinder temperatures get too high, lacquer and

varnish collect on pistons causing rings to stick, which

results in rapid wear. A worn ring usually takes on a

shiny or bright appearance.

Scratches on rings and pistons are caused by abrasive

material such as carbon, dirt, or pieces of hard metal.

Detonation damage occurs when a portion of fuel charge

ignites spontaneously from heat and pressure shortly

after ignition. This creates 2 ﬂ ame fronts, which meet

and explode to create extreme hammering pressures on

a speciﬁ c area of piston. Detonation generally occurs

from using low octane fuels.

Preignition or ignition of fuel charge before timed spark

can cause damage similar to detonation. Preignition

damage is often more severe than detonation damage.

Preignition is caused by a hot spot in combustion

chamber from sources such as glowing carbon deposits,

blocked cooling ﬁ ns, an improperly seated valve, or

wrong spark plug(s).

Replacement pistons are available in STD bore size, and

0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize.

Replacement pistons include new piston ring sets and

new piston pins.

Replacement ring sets are also available separately

for STD, 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.)

oversize pistons. Always use new piston rings when

installing pistons. Never use old rings.

Some important points to remember when servicing

piston rings:

Piston Style A

1. Cylinder bore must be de-glazed before service ring

sets are used.

2. If cylinder bore does not need re-boring and if old

piston is within wear limits and free of score or scuﬀ

marks, old piston may be reused.

3. Remove old rings and clean up grooves. Never

reuse old rings.

4. Before installing new rings on piston, place top 2

rings, each in turn, in its running area in cylinder

bore and check end gap. Top and middle

compression ring end gap clearance is

0.25/0.56 mm (0.0100/0.0224 in.) for a new bore, or

0.94 mm (0.037 in.) for a used bore.

5. After installing new compression (top and middle)

rings on piston, make sure top compression ring-to-

groove side clearance is 0.025/0.048 mm

(0.0010/0.0019 in.) and middle compression ring-to-

groove side clearance 0.015/0.037 mm

(0.0006/0.0015 in.). If side clearance is greater than

speciﬁ ed, a new piston must be used.

Disassembly/Inspection and Service

70 24 690 07 Rev. LKohlerEngines.com

Piston Style B

1. Cylinder bore must be de-glazed before service ring

sets are used.

2. If cylinder bore does not need re-boring and if old

piston is within wear limits and free of score or scuﬀ

marks, old piston may be reused.

3. Remove old rings and clean up grooves. Never

reuse old rings.

4. Before installing new rings on piston, place top 2

rings, each in turn, in its running area in cylinder

bore and check end gap.

80 mm bore engines: Top compression ring end gap

clearance is 0.100/0.279 mm (0.0039/0.0110 in.) for

a new bore, or 0.490 mm (0.0192 in.) for a used

bore. Middle compression ring end cap is

1.400/1.679 mm (0.0551/0.0661 in.) for a new bore,

or 1.941 mm (0.0764 in.) for a used bore.

83 mm bore engines: Top compression ring end gap

clearance is 0.189/0.277 mm (0.0074/0.0109 in.) for

a new bore, or 0.531 mm (0.0209 in.) for a used

bore. Middle compression ring end cap is

1.519/1.797 mm (0.0598/0.0708 in.) for a new bore,

or 2.051 mm (0.0808 in.) for a used bore.

5. After installing new compression (top and middle)

rings on piston, make sure top compression ring-to-

groove side clearance and is 0.030/0.070 mm

(0.0010/0.0026 in.) and middle compression ring-to-

groove side clearance 0.030/0.070 mm

(0.0010/0.0026 in.). If side clearance is greater than

speciﬁ ed, a new piston must be used.

Install New Piston Rings

Piston Ring Orientation

10°

Top Oil Ring Rail

Gap

Bottom Oil Ring Rail

Gap

Intermediate Ring

Gap

Oil Ring Expander

Gap

E Top Ring Gap F FLY Stamp

NOTE: Rings must be installed correctly. Ring

installation instructions are usually included with

new ring sets. Follow instructions carefully. Use

a piston ring expander to install rings. Install

bottom (oil control) ring ﬁ rst and top

compression ring last.

To install new piston rings, proceed as follows:

1. Oil control ring (bottom groove): Install expander and

then rails. Make sure ends of expander are not

overlapped.

2. Middle compression ring (center groove): Install

center ring using a piston ring installation tool. Make

sure identiﬁ cation mark is up or colored dye stripe

(if contained), is to left of end gap.

3. Top compression ring (top groove): Install top ring

using a piston ring expander. Make sure

identiﬁ cation mark is up or colored dye stripe

(if contained), is to left of end gap.

Disassembly/Inspection and Service

7124 690 07 Rev. L KohlerEngines.com

Connecting Rods

Oﬀ set, stepped-cap connecting rods are used in all

these engines.

Inspection and Service

Check bearing area (big end) for excessive wear,

score marks, running and side clearances (refer to

Speciﬁ cations). Replace rod and cap if scored or

excessively worn.

Service replacement connecting rods are available in

STD crankpin size and 0.25 mm (0.010 in.) undersize.

Undersized rods have an identiﬁ cation marking on lower

end of rod shank. Always refer to appropriate parts

information to ensure correct replacements are used.

Remove Crankshaft

Inspection and Service

Crankshaft Components and Detail

A Self-Tapping Screw B Flat Washer

C Plug D Crankshaft

Fillet Must Blend Smoothly with Bearing Journal

Surface

F High Point from Fillet Intersections

G 45° Minimum

H This Fillet Area Must Be Completely Smooth

NOTE: If crankpin is reground, visually check to insure

ﬁ llet blends smoothly with crankpin surface.

NOTE: To prevent repeat failures, camshaft and

crankshaft should always be replaced as a set.

Carefully pull crankshaft from crankcase.

Inspect gear teeth of crankshaft. If teeth are badly worn,

chipped, or some are missing, replacement of crankshaft

will be necessary.

Inspect crankshaft bearing surfaces for scoring,

grooving, etc. Measure running clearance between

crankshaft journals and their respective bearing bores.

Use an inside micrometer or telescoping gauge to

measure inside diameter of both bearing bores in vertical

and horizontal planes. Use an outside micrometer

to measure outside diameter of crankshaft main

bearing journals. Subtract journal diameters from their

respective bore diameters to get running clearances.

Check results against tolerances in Speciﬁ cations. If

running clearances are within speciﬁ cation, and there

is no evidence of scoring, grooving, etc., no further

reconditioning is necessary. If bearing surfaces are worn

or damaged, crankcase and/or oil pan will need to be

replaced.

Inspect crankshaft keyways. If worn or chipped,

replacement of crankshaft will be necessary.

Inspect crankpin for score marks or metallic pickup.

Slight score marks can be cleaned with crocus cloth

soaked in oil. If wear limits, as stated in Speciﬁ cations

are exceeded, it will be necessary to either replace

crankshaft or regrind crankpin to 0.25 mm (0.010 in.)

undersize. If reground, a 0.25 mm (0.010 in.) undersize

connecting rod (big end) must then be used to achieve

proper running clearance. Measure crankpin for size,

taper, and out-of-round.

Connecting rod journal can be ground 1 size under.

When grinding crankshaft, grinding stone deposits

can get caught in oil passages, which could cause

severe engine damage. Removing crankpin plug when

crankshaft is ground provides easy access for removing

any grinding deposits collected in oil passages.

Use following procedure to remove and replace plug.

Procedure to Remove Crankshaft Plug

1. Drill a 3/16" hole through plug in crankshaft.

2. Thread a 3/4" or 1" long self-tapping screw with a ﬂ at

washer into drilled hole. Flat washer must be large

enough to seat against shoulder of plug bore.

3. Tighten self-tapping screw until it draws plug out of

crankshaft.

Procedure to Install New Plug:

Use 1 single cylinder camshaft pin as a driver and tap

plug into plug bore until it seats at bottom of bore. Make

sure plug is tapped in evenly to prevent leakage.

Remove Flywheel End Oil Seal

Remove oil seal from crankcase.

Disassembly/Inspection and Service

72 24 690 07 Rev. LKohlerEngines.com

Crankcase

Inspection and Service

NOTE: Some CV25 engines feature POWER-BORE

™

cylinders, a special, patented nickel-silicone

plating process for increased power, superior oil

control, reduced exhaust emission, and virtually

permanent cylinder life. POWER-BORE

™

cylinders cannot be resized or honed as

described in following procedure. If a plated

cylinder bore is damaged or out of speciﬁ cation,

use a new miniblock or short block to repair

engine. Use following procedures for crankcases

with a cast iron sleeve.

Check all gasket surfaces to make sure they are free of

gasket fragments. Gasket surfaces must also be free of

deep scratches or nicks.

Check cylinder bore for scoring. In severe cases,

unburned fuel can cause scuﬃ ng and scoring of cylinder

wall. It washes necessary lubricating oils oﬀ piston and

cylinder wall. As raw fuel seeps down cylinder wall,

piston rings make metal to metal contact with wall.

Scoring of cylinder wall can also be caused by localized

hot spots resulting from blocked cooling ﬁ ns or from

inadequate or contaminated lubrication.

If cylinder bore is badly scored, excessively worn,

tapered, or out-of-round, resizing is necessary. Use an

inside micrometer to determine amount of wear (refer

to Speciﬁ cations), then select nearest suitable oversize

of either 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.).

Resizing to 1 of these oversizes will allow usage of

available oversize piston and ring assemblies. First,

resize using a boring bar, then use following procedures

for honing cylinder.

Honing

Detail

A 23°-33° Crosshatch

NOTE: Kohler pistons are custom-machined to exacting

tolerances. When oversizing a cylinder, it should

be machined exactly 0.25 mm (0.010 in.) or

0.50 mm (0.020 in.) over new diameter (refer to

Speciﬁ cations). A corresponding oversize Kohler

replacement piston will then ﬁ t correctly.

While most commercially available cylinder hones can

be used with either portable drills or drill presses, use

of a low speed drill press is preferred as it facilitates

more accurate alignment of bore in relation to crankshaft

crossbore. Honing is best accomplished at a drill speed

of about 250 RPM and 60 strokes per minute. After

installing coarse stones in hone, proceed as follows:

1. Lower hone into bore and after centering, adjust so

stones are in contact with cylinder wall. Use of a

commercial cutting-cooling agent is recommended.

2. With lower edge of each stone positioned even with

lowest edge of bore, start drill and honing process.

Move hone up and down while resizing to prevent

formation of cutting ridges. Check size frequently.

3. When bore is within 0.064 mm (0.0025 in.) of

desired size, remove coarse stones and replace

them with burnishing stones. Continue with

burnishing stones until bore is within 0.013 mm

(0.0005 in.) of desired size and then use ﬁ nish

stones (220-280 grit) and polish bore to its ﬁ nal size.

A crosshatch should be observed if honing is done

correctly. Crosshatch should intersect at

approximately 23°-33° oﬀ horizontal. Too ﬂ at an

angle could cause rings to skip and wear

excessively, and too steep an angle will result in high

oil consumption.

4. After resizing, check bore for roundness, taper, and

size. Use an inside micrometer, telescoping gauge,

or bore gauge to take measurements. These

measurements should be taken at 3 locations in

cylinder–at top, middle, and bottom. There are 2

measurements that should be taken (perpendicular

to each other) at all 3 locations.

Disassembly/Inspection and Service

7324 690 07 Rev. L KohlerEngines.com

Clean Cylinder Bore After Honing

Proper cleaning of cylinder walls following boring and/

or honing is very critical to a successful overhaul.

Machining grit left in cylinder bore can destroy an engine

in less than 1 hour of operation after a rebuild.

Final cleaning operation should always be a thorough

scrubbing with a brush and hot, soapy water. Use a

strong detergent capable of breaking down machining

oil while maintaining a good level of suds. If suds break

down during cleaning, discard dirty water and start again

with more hot water and detergent. Following scrubbing,

rinse cylinder with very hot, clear water, dry it completely,

and apply a light coating of engine oil to prevent rusting.

Measuring Piston-to-Bore Clearance

Piston Detail

Style A

Style B

Model Dimension A Dimension B

CV17/CV18/

CV20/CV22/

CV620/CV621/

CV640/CV641

6 mm (0.2362 in.) --

CV22/CV23/

CV670/CV680

6 mm (0.2362 in.) 13 mm (0.5118 in.)

CV620 674cc/

CV640 674cc

-- 13 mm (0.5118 in.)

CV25/CV730/

CV740/CV750

6 mm (0.2362 in.) 6 mm (0.2362 in.)

NOTE: Do not use a feeler gauge to measure piston-to-

bore clearance–it will yield inaccurate

measurements. Always use a micrometer.

Before installing piston into cylinder bore, it is

necessary clearance be accurately checked. This step

is often overlooked, and if clearances are not within

speciﬁ cations, engine failure will usually result.

Use following procedure to accurately measure piston-

to-bore clearance:

1. Use a micrometer and measure diameter of piston

above bottom of piston skirt and perpendicular to

piston pin.

2. Use an inside micrometer, telescoping gauge, or

bore gauge and measure cylinder bore. Take

measurement approximately 63.5 mm (2.5 in.) below

top of bore and perpendicular to piston pin.

3. Piston-to-bore clearance is diﬀ erence between bore

diameter and piston diameter (step 2 minus step 1).

Disassembly/Inspection and Service

74 24 690 07 Rev. LKohlerEngines.com

Breather/Oil Pan/Oil Reservoir/Piston Components

A Oil Fill/Dipstick B Dipstick Tube C Oil Seal D Breather Gasket

E Breather Cover F Flat Washer G Breather Reed H Governor Cross Shaft

I Oil Pan Gasket J Governor Gear K

Locking Tab Thrust

Washer

L Oil Screen (Style A)

M Gerotor Gear (Style A) N

Oil Pick-Up Tube

(Style A)

Oil Pump Assembly

(Style A)

P Piston Pin

Q Piston (Style A) R Piston Ring Set S Piston Ring Retainer T

Connecting Rod End

Cap

U Connecting Rod V Crankshaft W Camshaft X Piston (Style B)

Y Oil Pan (Style A) Z Oil Pan (Style B) AA

Oil Pump Assembly

(Style B)

Outer Gerotor Gear

(Style B)

Oil Pump Cover O-ring

(Style B)

AD Spring (Style B) AE Ball (Style B) AF Oil Screen (Style B)

Reassembly

7524 690 07 Rev. L KohlerEngines.com

Install Connecting Rods with Pistons and Rings

Piston and Connecting Rod Details

A Cylinder 1 B Cylinder 2

Connecting Rod Bolt Details

Type Torque

A 8 mm Straight Shank 22.7 N·m (200 in. lb.)

B 8 mm Step-Down 14.7 N·m (130 in. lb.)

C 6 mm Straight Shank 11.3 N·m (100 in. lb.)

NOTE: Cylinders are numbered on crankcase. Make

sure to install piston, connecting rod, and end

cap into its appropriate cylinder bore as

previously marked at disassembly. Do not mix

end caps and connecting rods.

NOTE: Proper orientation of piston/connecting rod

assemblies inside engine is extremely important.

Improper orientation can cause extensive wear

or damage. Be certain pistons and connecting

rods are assembled exactly as shown.

NOTE: Align chamfer of connecting rod with chamfer of

its mating end cap. When installed, ﬂ at faces of

connecting rods should face each other. Faces

with raised rib should be toward outside.

1. If piston rings were removed, see Disassembly/

Inspection and Service procedure to install new

rings.

2. Lubricate cylinder bore, piston, and piston rings with

engine oil. Compress rings using a piston ring

compressor.

3. Lubricate crankshaft journals and connecting rod

bearing surfaces with engine oil.

NOTE: Make sure engine is assembled using all

speciﬁ ed torque values, tightening sequences,

and clearances. Failure to observe speciﬁ cations

could cause severe engine wear or damage.

Always use new gaskets. Apply a small amount

of oil to threads of critical fasteners before

assembly, unless a sealant or Loctite

speciﬁ ed or preapplied.

Make sure all traces of any cleaner are removed before

engine is assembled and placed into operation. Even

small amounts of these cleaners can quickly break down

lubricating properties of engine oil.

Check oil pan, crankcase, cylinder heads, and valve

covers to be certain that all old sealing material has

been removed. Use gasket remover, lacquer thinner, or

paint remover to remove any remaining traces. Clean

surfaces with isopropyl alcohol, acetone, lacquer thinner,

or electrical contact cleaner.

Install Flywheel End Oil Seal

1. Make sure seal bore of crankcase is clean and free

of any nicks or burrs.

2. Apply a light coat of engine oil to outside diameter of

oil seal.

3. Drive oil seal into crankcase using a seal driver.

Make sure oil seal is installed straight and true in

bore and tool bottoms against crankcase.

Install Governor Cross Shaft

1. Lubricate governor cross shaft bearing surfaces in

crankcase with engine oil.

2. Slide small lower washer onto governor cross shaft

and install cross shaft from inside of crankcase.

3. 6 mm governor shaft: Install plain washer and then

insert hitch pin into smaller, lower hole of governor

cross shaft.

8 mm governor shaft: Install nylon washer onto

governor cross shaft, then start push-on retaining

ring. Hold cross shaft up in position, place a 0.50

mm (0.020 in.) feeler gauge on top of nylon washer,

and push retaining ring down shaft to secure.

Remove feeler gauge, which will have established

proper end play.

Install Crankshaft

Carefully slide ﬂ ywheel end of crankshaft through main

bearing in crankcase.

Reassembly

76 24 690 07 Rev. LKohlerEngines.com

4. Make sure Fly stamping on piston is facing towards

ﬂ ywheel side of engine. Use a hammer with a rubber

grip and gently tap piston into cylinder. Be careful

that oil ring rails do not spring free between bottom

of ring compressor and top of cylinder.

5. Install inner rod cap to connecting rod using screws.

Three diﬀ erent types of connecting rod bolts have

been used and each has a diﬀ erent torque value. If 8

mm straight shank type bolts are used, torque in

increments to 22.7 N·m (200 in. lb.). If 8 mm step-

down bolts are used, torque in increments to 14.7

N·m (130 in. lb.). If 6 mm straight shank bolts are

used, torque in increments to 11.3 N·m (100 in. lb.).

Illustrated instructions are provided in service rod

package.

6. Repeat above procedure for other connecting rod

and piston assembly.

Install Camshaft

1. Liberally apply camshaft lubricant to each cam lobe.

Lubricate camshaft bearing surfaces of crankcase

and camshaft with engine oil.

2. Position timing mark of crankshaft gear at 12 o’clock

position.

3. Turn governor cross shaft clockwise until lower end

of shaft contacts cylinder. Make sure cross shaft

remains in this position while installing camshaft.

4. Slide camshaft into bearing surface of crankcase,

positioning timing mark of camshaft gear at 6 o’clock

position. Make sure camshaft gear and crankshaft

gear mesh with both timing marks aligned.

Determining Camshaft End Play

1. Install shim removed during disassembly onto

camshaft.

2. Position camshaft end play checking tool on

camshaft.

3. Apply pressure on camshaft end play checking tool

(pushing camshaft toward crankshaft). Use a feeler

gauge to measure camshaft end play between shim

spacer and checking tool. Camshaft end play should

be 0.076/0.127 mm (0.003/0.005 in.).

4. If camshaft end play is not within speciﬁ ed range,

remove checking tool and replace shim as

necessary.

Several color-coded shims are available:

White: 0.69215/0.73025 mm (0.02725/0.02875 in.)

Blue: 0.74295/0.78105 mm (0.02925/0.03075 in.)

Red: 0.79375/0.83185 mm (0.03125/0.03275 in.)

Yellow: 0.84455/0.88265 mm (0.03325/0.03475 in.)

Green: 0.89535/0.99345 mm (0.03525/0.03675 in.)

Gray: 0.94615/0.98425 mm (0.03725/0.03875 in.)

Black: 0.99695/1.03505 mm (0.03925/0.04075 in.)

5. Reinstall end play checking tool and recheck end

play.

Oil Pump Assembly

Oil pump is mounted inside oil pan. If service was

required, and oil pump was removed, refer to

Disassembly/Inspection and Service.

Governor Gear Assembly

Governor gear assembly is located inside oil pan. If

service was required, and governor was removed, refer

to Disassembly/Inspection and Service.

Install Oil Seal in Oil Pan

Oil Seal Component and Detail

A 6.5 mm (0.255 in.) B Oil Seal

1. Check to make sure that there are no nicks or burrs

in crankshaft bore of oil pan.

2. Apply a light coat of engine oil to outside diameter of

oil seal.

3. Drive oil seal into oil pan using a seal driver. Make

sure oil seal is installed straight and true in bore, to

depth shown.

Reassembly

7724 690 07 Rev. L KohlerEngines.com

Install Oil Pan Assembly

Sealant Pattern

1.5 mm (1/16 in.)

bead of sealant.

Fill groove between

points with RTV

RTV must be all

around O-ring groove

Torque Sequence

RTV sealant is used as a gasket between oil pan and

crankcase on CV17-23 engines. CV25-750 engines use

an oil pan gasket. Refer to Tools and Aids for a listing

of approved sealants. Always use fresh sealant. Using

outdated sealant can result in leakage.

1. Be sure sealing surfaces have been cleaned and

prepared. Install a new O-ring in oil pan.

2. Check to make sure that there are no nicks or burrs

on sealing surfaces of oil pan or crankcase.

3. Apply a 1.5 mm (1/16 in.) bead of sealant to sealing

surface of oil pan on CV17-23 engines. CV25-750

engines use a new gasket. Before installing gasket,

check dowel pin on oil ﬁ lter side of crankcase. If a

split style dowel pin is contained, replace it with a

closed seam style pin provided with new gasket.

4. Make sure end of governor cross shaft is lying

against bottom of cylinder 1 inside crankcase.

5. Install oil pan to crankcase. Carefully seat camshaft

and crankshaft into their mating bearings. Rotate

crankshaft slightly to help engage oil pump and

governor gear meshes.

6. Install screws securing oil pan to crankcase. Torque

fasteners to 24.4 N·m (216 in. lb) following

sequence. On some engines one mounting screw is

plated. Plated screw is typically installed in hole

location 6.

Reassembly

78 24 690 07 Rev. LKohlerEngines.com

Flywheel/Ignition Components

A Flywheel Screw B Debris Screen

C Support Ring D Fan

E Magnet F Stator

G Ignition Module H Stud

I Screw J Woodruﬀ Key

K Manifold L Backing Plate

M Flywheel N Washer

O Support

Install Stator and Backing Plates

1. Apply pipe sealant with Teﬂ on

(Loctite

PST

592™

Thread Sealant or equivalent) to stator mounting

holes.

2. Position stator aligning mounting holes so that leads

are at bottom, towards crankcase.

3. Install and torque screws to 6.2 N·m (55 in. lb.).

4. Route stator leads in crankcase channel, then install

backing plates and stator wire bracket (if used).

Secure with screws. Torque screws to 7.3 N·m

(65 in. lb.).

Install Flywheel

CAUTION

Damaging Crankshaft and Flywheel can

cause personal injury.

Using improper procedures can lead to broken

fragments. Broken fragments could be thrown from

engine. Always observe and use precautions and

procedures when installing ﬂ ywheel.

NOTE: Before installing ﬂ ywheel, make sure crankshaft

taper and ﬂ ywheel hub are clean, dry, and

completely free of any lubricants. Presence of

lubricants can cause ﬂ ywheel to be over

stressed and damaged when screw is torqued to

speciﬁ cations.

NOTE: Make sure ﬂ ywheel key is installed properly in

keyway. Flywheel can become cracked or

damaged if key is not properly installed.

1. Install woodruﬀ key into keyway of crankshaft. Make

sure key is properly seated and parallel with shaft

taper.

2. Install ﬂ ywheel onto crankshaft being careful not to

shift woodruﬀ key.

3. Install screw and washer.

4. Use a ﬂ ywheel strap wrench or holding tool to hold

ﬂ ywheel. Torque screw securing ﬂ ywheel to

crankshaft to 66.4 N·m (49 ft. lb.).

Install Fan and Debris Screen

NOTE: Position locating tabs on back of fan in recesses

of ﬂ ywheel.

1. Install fan onto ﬂ ywheel using screws (engines with

plastic debris screen).

2. Torque screws to 9.9 N·m (88 in. lb.).

3. If engine has a plastic debris screen, snap screen

onto fan. Due to possible damage to posts during

removal, install retainers on diﬀ erent posts from

which they were removed. Start retainers by hand,

then push them down with a 13 mm (1/2”) socket

until they lock. If engine has a metal screen, it will be

installed later.

Reassembly

7924 690 07 Rev. L KohlerEngines.com

Install Supports for Metal Debris Screen

1. If a metal debris screen is used, with threaded individual supports, install a spacer washer on external threads.

Apply blue Loctite

242

(removable) to threads. Install supports as shown.

2. Tighten supports with a torque wrench to 9.9 N·m (88 in. lb.). Debris screen will be installed to supports after

blower housing is in place.

Cylinder Head Components

A Valves B Cylinder Head C Spark Plug D Nut

E Hydraulic Lifter F Cap G Valve Stem Seal H Valve Spring Keeper

I Valve Spring J

Valve Spring

Retainer

K Rocker Arm Pivot L Push Rod

M Rocker Arm N Screw O Valve Cover O-ring P Grommet

Q Valve Cover R Gasket

Install Hydraulic Lifters

NOTE: Hydraulic lifters should always be installed in

same position as before disassembly. Exhaust

lifters are located on output shaft (oil pan) side

of engine while intake lifters are located on fan

side of engine. Cylinder numbers are embossed

on top of crankcase and each cylinder head.

1. Refer to Disassembly/Inspection and Service for

hydraulic/bleeding lifter procedures.

2. Apply camshaft lubricant to bottom surface of each

lifter. Lubricate hydraulic lifters and lifter bores in

crankcase with engine oil.

3. Note mark or tag identifying hydraulic lifters as either

intake or exhaust and cylinder 1 or cylinder 2. Install

hydraulic lifters into their appropriate locations in

crankcase. Do not use a magnet.

4. If breather reeds and stops were removed from

crankcase, reinstall them at this time and secure

with screw. Torque screw to 4.0 N·m (35 in. lb.).

Valve Stem Seals

These engines use valve stem seals on intake valves

and occasionally on exhaust valves. Use a new seal

whenever valve is removed or if seal is deteriorated or

damaged in any way. Never reuse an old seal.

Reassembly

80 24 690 07 Rev. LKohlerEngines.com

Assemble Cylinder Heads

Prior to installation, lubricate all components with engine

oil, paying particular attention to lip of valve stem seal,

valve stems, and valve guides. Install in order listed

below using a valve spring compressor.

● Intake and exhaust valves.

● Valve spring caps.

● Valve springs.

● Valve spring retainers.

● Valve spring keepers.

Install Cylinder Heads

Torque Sequence

NOTE: Cylinder heads must be attached with original

type of mounting hardware, using either screws,

or mounting studs with nuts and washers. Heads

are machined diﬀ erently for studs than for

screws, so fastening method cannot be altered

unless heads are being replaced. Do not

intermix components.

NOTE: Match numbers embossed on cylinder heads

and crankcase.

Heads Secured With Screws

1. Check to make sure there are no nicks or burrs on

sealing surfaces of cylinder head or crankcase.

2. Install a new cylinder head gasket (with printing up).

3. Install cylinder head and start four screws.

4. Torque screws in two stages; ﬁ rst to 22.6 N·m (200

in. lb.), then ﬁ nally to 41.8 N·m (370 in. lb.), following

sequence shown.

Heads Secured With Mounting Studs, Nuts, and

Washers

1. Check to make sure there are no nicks or burrs on

sealing surfaces of cylinder head or crankcase.

2. If all studs were left intact, go to Step 6. If any studs

were disturbed or removed, install new studs as

described in Step 3. Do not use/reinstall any

loosened or removed studs.

3. Install new mounting stud(s) into crankcase.

a. Thread and lock 2 mounting nuts together on

smaller diameter threads.

b. Thread opposite end of stud, with preapplied

locking compound, into crankcase, until speciﬁ ed

height from crankcase surface is achieved. When

threading in studs, use a steady tightening motion

without interruption until proper height is

obtained. Otherwise frictional heat from engaging

threads may cause locking compound to set up

prematurely.

Studs closest to lifters must have an exposed

height of 75 mm (2 15/16 in.).

Studs furthest from lifters must have an exposed

height of 68 mm (2 3/4 in.).

c. Remove nuts and repeat procedure as required.

4. Check that dowel pins are in place and install a new

cylinder head gasket (printing up).

5. Install cylinder head. Match numbers on cylinder

heads and crankcase. Make sure head is ﬂ at on

gasket and dowel pins.

6. Lightly lubricate exposed (upper) threads of studs

with engine oil. Install a new ﬂ at washer and nut onto

each mounting stud. Torque nuts in two stages; ﬁ rst

to 16.9 N·m (150 in. lb.), then ﬁ nally to 35.5 N·m

(315 in. lb.), following sequence shown.

Install Push Rods and Rocker Arms

NOTE: Push rods should always be installed in same

position as before disassembly.

NOTE: Two diﬀ erent screws have been used to secure

rocker arms/pivots. Black screws are used with

heads that have a rocker pivot hole depth of

approximately 21 mm (0.83 in.). Silver screws

are used with heads that have a rocker pivot

hole depth of approximately 35 mm (1.38 in.).

1. Note mark or tag identifying push rod as either

intake or exhaust and cylinder 1 or 2. Dip ends of

push rods in engine oil and install, making sure that

each push rod ball seats in its hydraulic lifter socket.

2. Apply grease to contact surfaces of rocker arms and

rocker arm pivots. Install rocker arms and rocker arm

pivots on one cylinder head, and start screws.

3. Torque black screws to 18.1 N·m (160 in. lb.).

Torque silver screws to 13.6 N·m (120 in. lb.).

4. Use a spanner wrench or rocker arm lifting tool, to lift

rocker arms and position push rods underneath.

5. Repeat above steps for remaining cylinder. Do not

interchange parts from cylinder heads.

6. Rotate crankshaft to check for free operation of

valve train. Check clearance between valve spring

coils at full lift. Minimum allowable clearance is 0.25

mm (0.010 in.).

Check Assembly

Rotate crankshaft a minimum of two revolutions to check

longblock assembly and overall proper operation.

Install Spark Plugs

1. Check gap using wire feeler gauge. Adjust gap to

0.76 mm (0.030 in.).

2. Install plug into cylinder head.

3. Torque plug to 27 N·m (20 ft. lb.).

Reassembly

8124 690 07 Rev. L KohlerEngines.com

Install Ignition Modules

1. Rotate ﬂ ywheel to position magnet away from

ignition module bosses.

2. On engines equipped with SMART-SPARK

™,

both

modules are installed similarly with tabs out.

On engines not equipped with SMART-SPARK

modules are installed on cylinder 1 with single kill

tab away from cylinder/towards you, and on cylinder

2 with single kill tab towards cylinder/away from you.

3. Install each ignition module to crankcase bosses

with screws (hex ﬂ ange or allen head, based on

model). Slide modules up as far away from ﬂ ywheel

as possible and snug screws to hold them in that

position.

4. Rotate ﬂ ywheel to position magnet directly under

one ignition module.

5. Insert a 0.30 mm (0.012 in.) ﬂ at feeler gauge

between magnet and ignition module. Loosen

screws enough to allow magnet to pull module

against feeler gauge.

6. Torque screws to 4.0-6.2 N·m (35-55 in. lb.).

7. Repeat steps 4 through 6 for other ignition module.

8. Rotate ﬂ ywheel back and forth checking for

clearance between magnet and ignition modules.

Make sure magnet does not strike modules. Check

gap with a feeler gauge and readjust if necessary.

Final air gap: 0.280/0.330 mm (0.011/0.013 in.).

Install Intake Manifold

Torque Sequence

NOTE: If wires were disconnected from ignition modules

on engines with SMART-SPARK

™

, reattach

leads and seal base of terminal connectors with

GE/Novaguard G661 or equivalent dielectric

compound. Beads should overlap between

terminals to form a solid bridge of compound. Do

not put any compound inside terminals.

24 584 15-S ignition modules have a separator

barrier between terminals. On these modules,

seal base of terminals, but it is not necessary to

have overlapping beads of sealant between

connections.

1. Install intake manifold and new gaskets or O-rings

(plastic manifold), with wiring harness attached, to

cylinder heads. Slide any wiring harness clips onto

appropriate bolts before installing. Make sure

gaskets are in proper orientation. Using sequence

shown, torque screws in two increments, ﬁ rst to

7.4 N·m (66 in. lb.), then to 9.9 N·m (88 in. lb.).

2. Connect kill lead to tab terminal on standard ignition

modules.

Install Breather Cover and Inner Baﬄ es

Breather Cover Torque Sequence

RTV sealant was used on early models between

breather cover and crankcase. A gasket with imprinted

sealant beads is now used and recommended. Install as

follows.

1. Be sure sealing surfaces of crankcase and breather

cover are clean of old gasket material or RTV

sealant. Do not scrape surfaces as this could result

in leakage.

2. Check to make sure there are no nicks or burrs on

sealing surfaces.

3. Position breather gasket and cover on crankcase.

Install ﬁ rst screws in locations 3 and 4 as shown.

Finger tighten at this time.

4. Install inner baﬄ es using remaining screws and

ﬁ nger tighten. Do not torque screws at this time; they

will be tightened after blower housing and outer

baﬄ es are installed.

Reassembly

82 24 690 07 Rev. LKohlerEngines.com

Install Blower Housing and Outer Baﬄ es

Wires on Starter Side of Engine

Wires on Oil Filter Side of Engine

NOTE: Do not completely tighten screws until all items

are installed to allow shifting for hole alignment.

1. Pull wire harness and spark plug leads out through

appropriate openings in shrouding.

2. Slide blower housing into position over front edge of

inner baﬄ es. Start a few of screws to hold it in place.

3. Position outer baﬄ es and secure using screws (two

long, two short) in front mounting holes (into cylinder

head), including any lifting strap or attached

bracket(s). Install two short screws in upper

mounting holes of outer baﬄ es (into backing plates).

Use short screw on left side to mount wire harness

bracket. Be sure any leads are routed out through

proper oﬀ sets or notches, so they will not be pinched

between blower housing and baﬄ es.

4. Tighten all shrouding fasteners. Torque blower

housing screws to 6.2 N·m (55 in. lb.) in a new hole,

or to 4.0 N·m (35 in. lb.) in a used hole. Torque

shorter M5 side baﬄ e screws to 4.0 N·m (35 in. lb.).

Torque M5 side baﬄ e screws (into cylinder head) to

6.2 N·m (55 in. lb.) in a new hole, or to 4.0 N·m

(35 in. lb.) in a used hole. Torque two lower M6

baﬄ e mounting screws to 10.7 N·m (95 in. lb.) in a

new hole, or to 7.3 N·m (65 in. lb.) in a used hole.

5. If engine had a plastic debris screen that overlaps

blower housing, reinstall it now. Torque mounting

screws to 4.0 N·m (36 in. lb.). For a metal screen,

apply Loctite

242

to screw threads and torque

screws to 9.9 N·m (88 in. lb.).

6. Torque breather cover screws to 11.3 N·m (100 in.

lb.) into new holes or 7.3 N·m (65 in. lb.) into used

holes in sequence shown. Note ﬁ rst screw is torqued

a second time.

Install Oil Sentry

™

(if equipped)

1. Apply pipe sealant with Teﬂ on

(Loctite

PST

592™

Thread Sealant or equivalent) to threads of Oil

Sentry

™

switch and install it into breather cover.

Torque to 4.5 N·m (40 in. lb.).

2. Connect wire lead (green) to Oil Sentry

™

terminal.

Install Control Panel (if equipped)

1. Install panel to blower housing.

2. Connect throttle control shaft to throttle control

bracket.

3. Connect choke control cable to throttle control

bracket.

4. Connect Oil Sentry

™

indicator light wires.

Reconnect Rectiﬁ er-Regulator

1. Install rectiﬁ er-regulator in blower housing if

removed previously, then connect rectiﬁ er-regulator

ground lead with washer and silver screw through

eyelet. If a grounding bracket is used, secure with

mounting screw and washer, against outer side of

rectiﬁ er-regulator.

2. Install B+ terminal/lead into center position of

rectiﬁ er-regulator plug and connect plug to rectiﬁ er-

regulator.

SMART-SPARK

™

Module

On engines with SMART-SPARK

™

, reinstall SAM module

to blower housing or cylinder baﬄ e. Do not over-tighten

retaining screws.

Reassembly

8324 690 07 Rev. L KohlerEngines.com

Install Valve Covers

Torque Sequence

NOTE: Do not scrape old RTV sealant (if used) oﬀ

sealing surface of cylinder head as this could

cause damage and result in leaks. Use of gasket

remover solvent (paint remover) is

recommended.

Three valve cover designs have been used. First type

used a gasket and RTV sealant between cover and

sealing surface of cylinder head. Second type had a

black O-ring installed in a groove on underside of cover

and may have metal spacers in bolt holes. Latest design

uses a yellow or brown O-ring, with bolt hole spacers

molded in place. Tightening torque diﬀ ers between

gasket and O-ring style covers. Kits are available for

converting to latest O-ring type covers. Diﬀ erences are

pointed out in following installation steps.

1. If using gasket or sealant type cover, prepare sealing

surfaces of cylinder head and cover, refer to Tools

and Aids for approved sealants. Always use fresh

sealant. Using outdated sealant could result in

leakage. With O-ring type covers, make sure sealing

surfaces are clean.

2. Make sure there are no nicks or burrs on sealing

surfaces.

3. For covers requiring RTV sealant, apply a 1.5 mm

(1/16 in.) bead to sealing surface of both cylinder

heads, install a new cover gasket on each, then

apply a second bead of sealant on top surface of

gaskets. For O-ring type covers, install a new O-ring

in groove of each cover. Do not use gaskets or RTV

sealant.

4. Position covers on cylinder heads. Locate cover with

oil separator hole on cylinder 1. If loose spacers

were used, insert a spacer in each screw hole.

Install screws in each cover and ﬁ nger tighten.

5. Torque valve cover fasteners to proper speciﬁ cation

using sequence shown, unless screws also attach

heavy-duty air cleaner main support bracket or other

components. Installation and torquing of screws will

be performed after these parts are installed.

Torque Speciﬁ cations-Covers

Gasket/RTV 3.4 N·m (30 in. lb.)

Black O-ring

w/shoulder screws

w/screws and spacers

5.6 N·m (50 in. lb.)

9.9 N·m (88 in. lb.)

Yellow or Brown O-ring

w/integral spacers 9.0 N·m (80 in. lb.)

Install Carburetor

WARNING

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings,

away from sparks or ﬂ ames. Spilled fuel could ignite

if it comes in contact with hot parts or sparks from

ignition. Never use gasoline as a cleaning agent.

1. Install a new carburetor gasket. Make sure all holes

align and are open.

2. Install carburetor, throttle linkage, choke linkage, and

governor lever as an assembly. If a plastic intake

manifold is used and/or carburetor is equipped with

a fuel solenoid, reconnect ground and main leads.

Reassembly

84 24 690 07 Rev. LKohlerEngines.com

Control Panel Components

A Nut B Lock Nut

C Flat Washer D Control Bracket

E Carburetor F Air Cleaner Gasket

G Governor Lever H Governor Spring

I Throttle Shaft J Bracket

K Spacer L

Throttle Control

Lever

M Linkage Spring N Throttle Linkage

O Carburetor Gasket P Choke Linkage

Q Choke Lever R Screw

S Throttle Shaft Spring

Install External Governor Controls

1. Install governor lever onto governor cross shaft.

2. Make sure throttle linkage is connected to governor

lever and throttle lever on carburetor.

Two-barrel carburetor models: Move control panel

into position on blower housing and connect choke

linkage into bushing/lever from backside. Make

certain that control shaft oﬀ set is back and towards

cylinder side 2. Connect throttle linkage and spring

to governor lever.

3. Move governor lever toward carburetor as far as it

will go (wide-open throttle) and hold in position.

4. Insert a long thin rod or tool into hole on cross shaft

and rotate shaft counterclockwise (viewed from end)

as far as it will turn, then torque nut to 6.8 N·m (60

in. lb.).

5. Reconnect lead wire to fuel shut-oﬀ solenoid (if

equipped).

6. Install lower support control bracket (if equipped with

a control panel).

7. Secure control panel to blower housing with screws

(if not equipped with heavy-duty air cleaner).

8. Assemble throttle control shaft to control bracket.

9. Assemble choke control to control bracket.

10. Connect Oil Sentry

™

Indicator light wires. Attach

governor spring to governor lever. See appropriate

charts.

Install Throttle and Choke Controls

Throttle and Choke Components

A Choke Lever B

Throttle Control

Lever

Throttle Actuator

Lever

D Lock Nut

E Choke Return Spring F

Speed Control

Bracket

G Flat Washer(s) H Wave Washer

I Screw

1. One-Barrel Carburetor Models: Connect choke

linkage to carburetor and choke actuator lever.

2. One-Barrel Carburetor Models: Install standard

throttle control bracket and air cleaner support

bracket (if used) to cylinder heads using screws.

Torque screws to 10.7 N·m (95 in. lb.) into new

holes, or 7.3 N·m (65 in. lb.) into used holes.

3. Connect governor spring from throttle control bracket

to appropriate hole in governor lever, as indicated in

applicable chart. Note that hole positions are

counted from pivot point of governor lever.

Reassembly

8524 690 07 Rev. L KohlerEngines.com

Governor Lever Hole Position (6 mm)

A Governor Lever B Governed Idle Hole

C Hole 1 D Hole 2

E Hole 3 F Hole 4

G Hole 5 H Hole 6

6 mm Governor Lever and Hole Position/RPM Chart

High Idle

RPM

Governor Lever

Hole No.

Governor

Spring Color

Code

3801-4000 6 Clear

3601-3800 5 Clear

3451-3600 4 Clear

3301-3450 3 Clear

3101-3300 5 Purple

2951-3100 4 Purple

2800-2950 3 Purple

3750* 4 Clear

3150* 4 Purple

*5% Regulation (others 10%)

8 mm Governor Lever and Hole Position/RPM Charts

A Governor Lever B Hole 1

C Hole 2 D Hole 3

E Hole 4

CV18 Engines

Intended

Maximum RPM

Standard

Throttle Control

Engine Mounted

Throttle Control

Pivot Shaft

High

Idle

WOT

Spring

Color

Hole

No.

Spring

Color

Hole

No.

3888

3780

3672

3564

3456

3348

3240

3132

3024

3600

3500

3400

3300

3200

3100

3000

2900

2800

Green

Blue

Orange

Clear

Red

Purple

Blue

Orange

Black

Orange

Green

Blue

Orange

Green

Blue

Purple

Blue

Green

CV20-740 Engines with 0.0299 + 0.003 in. Thick

(22 GA) Throttle Limiter

Intended

Maximum RPM

Standard

Throttle Control

Engine Mounted

Throttle Control

Pivot Shaft

High

Idle

WOT

Spring

Color

Hole

No.

Spring

Color

Hole No.

3888

3780

3672

3564

3456

3348

3240

3132

3024

3600

3500

3400

3300

3200

3100

3000

2900

2800

Green

Blue

Orange

Clear

Red

Purple

Blue

Orange

Black

Purple

Black

Red

Purple

Black

Red

Clear

Red

Green

CV17, CV20-740 Engines Without Throttle Limiter

Intended

Maximum RPM

Standard

Throttle Control

Engine Mounted

Throttle Control

Pivot Shaft

High

Idle

WOT

Spring

Color

Hole

No.

Spring

Color

Hole No.

3888

3780

3672

3564

3456

3348

3240

3132

3024

3600

3500

3400

3300

3200

3100

3000

2900

2800

Red

Purple

Black

Red

Purple

Blue

Orange

Clear

Red

Blue

Orange

Black

Orange

Green

Blue

Orange

Black

Red

Reassembly

86 24 690 07 Rev. LKohlerEngines.com

CV750 Engines

Governor Shaft

Conﬁ guration

Intended Maximum RPM With Governed Idle Systems

High Idle WOT Spring Color Hole No.

Standard

(Parent Material)

3888

3780

3672

3564

3456

3348

3600

3500

3400

3300

3200

3100

Clear

Orange

Blue

Red

Clear

Install Electric Starter Motor

1. Install starter motor using screws. Position lift

bracket to also secure dipstick tube. Some inertia-

drive starters have a pinion cover and spacers on

starter bolts.

2. Torque screws to 15.3 N·m (135 in. lb.).

3. On models with a solenoid shift starter, connect

leads to solenoid.

4. Install dipstick tube and align mounting hole with

threaded hole in lift bracket. Secure with M5 screw.

Torque screw to 4.0 N·m (35 in. lb.).

Install Fuel Pump

WARNING

Explosive Fuel can cause ﬁ res and severe

burns.

Do not ﬁ ll fuel tank while engine is hot or

running.

Gasoline is extremely ﬂ ammable and its vapors can

explode if ignited. Store gasoline only in approved

containers, in well ventilated, unoccupied buildings,

away from sparks or ﬂ ames. Spilled fuel could ignite

if it comes in contact with hot parts or sparks from

ignition. Never use gasoline as a cleaning agent.

Fuel Pump Components

A Blower Housing Clip B Outlet Fuel Line

C Pulse Line D Inlet Fuel Line

E Fuel Line Clamp F Fuel Filter

G Fuel Pump

NOTE: Fuel pumps may be made of metal or plastic. If

a new fuel pump is being installed, make sure

orientation of new pump is consistent with

removed pump. Internal damage may occur if

installed incorrectly.

1. Install fuel pump and lines as an assembly. Connect

pulse line to crankcase vacuum ﬁ tting.

2. Install fuel pump using screws. Torque screws to 2.3

N·m (20 in. lb.).

3. Connect fuel lines.

Install Air Cleaner Assembly

Low-Proﬁ le and Commercial Mower Air Cleaners

1. Connect breather hose and attach breather

separator to valve cover. Position hose in cutout of

blower housing (later models).

2. Position a new gasket and air cleaner base on studs

while carefully pulling loose end of rubber breather

hose through base until properly seated (collars

sealed against each side of base.

3. Secure air cleaner base and bracket, or spit-back

cup with baﬄ e, using hex ﬂ ange nuts. If a lower air

cleaner bracket is used, install M5 screws through

lower section of base. Torque hex ﬂ ange nuts to

6.2-7.3 N·m (55-65 in. lb.), and two lower M5 screws

(when applicable) to 4.0 N·m (35 in. lb.).

4. Install air cleaner components, refer to Air Cleaner/

Intake.

Heavy-Duty Air Cleaners

1. Install a new air cleaner base gasket.

2. Attach main support bracket to four inboard valve

cover screw locations. Make sure each of mounting

holes has a loose or integral spacer. Leave screws

slightly loose.

3. Install elbow adapter onto mounting studs. Secure

with, and torque hex ﬂ ange nuts to 6.2-7.3 N·m

(55-65 in. lb.).

4. Install and tighten screws securing air cleaner

mounting bracket and control panel to blower

housing.

5. Torque valve cover/mounting bracket screws to

proper speciﬁ cation and torque sequence listed in

Reassembly-Install Valve Covers.

6. Two-barrel carburetor models only: attach choke

return spring to bottom of main control bracket.

Reassembly

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Install Muﬄ er

1. Install port liners (if equipped). Install muﬄ er and

attaching hardware to muﬄ er bracket. Torque

screws to 9.9 N·m (88 in. lb.).

2. Install hex ﬂ ange nuts to exhaust studs. Torque nuts

to 24.4. N·m (216 in. lb.).

Install Oil Cooler (if equipped)

Oil cooler can now be installed to engine. Two diﬀ erent

styles are used.

1. Depending on style used, reverse removal

procedure from Disassembly.

2. Secure cooler or adapter to oil pan with oil ﬁ lter

nipple. Torque oil ﬁ lter nipple to 27 N·m (20 ft. lb.).

Install Oil Filter and Fill Crankcase with Oil

NOTE: Make sure that both oil drain plugs are installed

and torqued to above speciﬁ cations to prevent

oil leakage.

1. Install oil drain plug(s). Torque plug(s) to 13.6 N·m

(10 ft. lb.). If oil drain valve is used, make sure valve

body is closed and cap is on.

2. Place new ﬁ lter in shallow pan with open end up. Fill

with new oil until oil reaches bottom of threads. Allow

2 minutes for oil to be absorbed by ﬁ lter material.

3. Apply a thin ﬁ lm of clean oil to rubber gasket on oil

ﬁ lter.

4. Refer to instructions on oil ﬁ lter for proper

installation.

5. Fill crankcase with new oil. Level should be at top of

indicator on dipstick.

6. Reinstall oil ﬁ ll cap/dipstick and tighten securely.

Connect Spark Plug Leads

Connect leads to spark plugs.

Prepare Engine for Operation

Engine is now completely reassembled. Before starting

or operating engine, be sure to do following.

1. Make sure all hardware is tightened securely.

2. Make sure oil drain plugs, Oil Sentry

™

pressure

switch, and a new oil ﬁ lter are installed.

3. Adjust carburetor, idle fuel needle, or idle speed

adjusting screw as necessary.

Testing Engine

It is recommended that engine be operated on a test

stand or bench prior to installation in piece of equipment.

1. Set engine up on a test stand. Install an oil pressure

gauge. Start engine and check to be certain that oil

pressure (20 psi or more) is present. Run engine at

idle for 2-3 minutes, then 5-6 minutes more between

idle and midrange. Adjust carburetor mixture settings

as necessary (as available).

2. Adjust idle speed screw and high-speed stop as

necessary. Make sure maximum engine speed does

not exceed 3750 RPM (no load).

Reassembly

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