Kohler CH940,CH1000, CH940, CH1000 Service Manual

CH940-CH1000

Service Manual

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.

2 Safety
3 Maintenance

5 Specifi cations
13 Tools and Aids
16 Troubleshooting
20 Air Cleaner/Intake
21 Fuel System and Governor
28 Lubrication System
30 Electrical System
46 Disassembly
55 Reassembly

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KohlerEngines.com

Safety

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.

Engine exhaust gases contain
poisonous carbon monoxide.
Carbon monoxide is odorless,
colorless, and can cause death if
inhaled.

CAUTION

Electrical Shock can
cause injury.

Do not touch wires while
engine is running.

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.

2 62 690 01 Rev. CKohlerEngines.com

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.

Maintenance

WARNING

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 fi lter minder. Air Cleaner/Intake

Every 25 Hours or Annually¹

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

Every 150 Hours¹

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

● Change oil. Oil fi lter is recommended. Lubrication System

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

Before working on engine or equipment, disable engine as
follows: 1) Disconnect spark plug lead(s). 2) Disconnect
negative (–) battery cable from battery.

Every 150 Hours

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

● Replace fuel fi lter. Fuel System and Governor

● Check oil cooler fi ns, clean as necessary. Lubrication System

Every 300 Hours

● Change oil fi lter. Lubrication System

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

Every 500 Hours²

● Have crankshaft splines lubricated.

Every 600 Hours

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

● Replace spark plugs and set gap. Electrical System

1

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

2

Have a Kohler authorized dealer perform this service.

Repairs/Service Parts

We recommend that you use a Kohler authorized dealer for all maintenance, service, and replacement parts for
engine. To fi nd a Kohler authorized dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada).

362 690 01 Rev. C KohlerEngines.com

Maintenance

Oil Recommendations

We recommend use of Kohler oils for best performance.
Other high-quality detergent oils (including synthetic)
of API (American Petroleum Institute) service class SJ
or higher are acceptable. Select viscosity based on
air temperature at time of operation as shown in table
below.

Fuel Recommendations

WARNING

Explosive Fuel can cause fi res and severe
burns.

Do not fi ll fuel tank while engine is hot or
running.

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.
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.

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; effects 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.

4 62 690 01 Rev. CKohlerEngines.com

Engine Dimensions with Heavy-Duty Air Cleaner

Specifi cations

Dimensions in millimeters.

Inch equivalents shown in [ ].

562 690 01 Rev. C KohlerEngines.com

Specifi cations

Engine Dimensions with Low-Profi le Air Cleaner

Dimensions in millimeters.

Inch equivalents shown in [ ].

6 62 690 01 Rev. CKohlerEngines.com

Specifi cations

Engine Identifi cation 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 . . . . . . . . . . . . . . . . . . . . . CH940

Command Engine

Horizontal Shaft

Numerical Designation

Specifi cation . . . . . . . . . . . . . . . CH940-0001

Serial . . . . . . . . . . . . . . . . . . . . . 3923500328

Year Manufactured Code Factory Code
Code Year
39 2009
40 2010
41 2011

General Specifi cations

3

CH940 CH960 CH980 CH1000

Bore 90 mm (3.54 in.)
Stroke 78.5 mm (3.1 in.)
Displacement 999 cc (61 cu. in.)
Oil Capacity (w/fi lter) (approximate) 2.7 L (2.9 U.S. qt.)
Maximum Angle of Operation (@ full oil level)

4

25°

Torques

CH940 CH960 CH980 CH1000

Blower Housing and Steel Metal

M6 Shoulder Screw
New, Untapped Hole (casting)
Used, Tapped Hole (casting)
New, Extruded Hole (sheet metal)
Used, Extruded Hole (sheet metal)
Mounting Clip (valley baffl e)

10.7 N·m (95 in. lb.)

7.3 N·m (65 in. lb.)

4.0 N·m (35 in. lb.)

2.0 N·m (18 in. lb.)

2.5 N·m (22 in. lb.)

M6 Screw
New, Untapped Hole (casting)
Used, Tapped Hole (casting)

10.7 N·m (95 in. lb.)

7.3 N·m (65 in. lb.)
Rectifi er-Regulator Fastener 2.0 N·m (18 in. lb.)
Oil Cooler Fastener 2.2 N·m (20 in. lb.)

Carburetor, Intake Manifold, and Air Cleaner

Intake Manifold Mounting Fastener
Torque in Two Stages fi rst to 16.9 N·m (150 in. lb.)

Carburetor/Air Cleaner Mounting Nut 7.9 N·m (70 in. lb.)
Air Cleaner Mounting Screw (into intake manifold) 9.9 N·m (88 in. lb.)

Closure Plate

Closure Plate Fastener 24.4 N·m (216 in. lb.)

3

Values are in Metric units. Values in parentheses are English equivalents. Lubricate threads with engine oil prior to

assembly.

4

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

fi nally to 22.6 N·m (200 in. lb.)

762 690 01 Rev. C KohlerEngines.com

Specifi cations

Torques

CH940 CH960 CH980 CH1000

Connecting Rod

Cap Fastener (torque in increments) 11.3 N·m (100 in. lb.)

Control Bracket

Mounting Screw (into intake manifold from air cleaner) 9.9 N·m (88 in. lb.)

Crankcase

Breather Cover Fastener 5.7 N·m (51 in. lb.)
Oil Drain Plug 21.4 N·m (16 ft . lb.)

Cylinder Head

Cylinder Head Fastener
Head Bolt - Torque in Two Stages fi rst to 22.6 N·m (200 in. lb.)

fi nally to 45.2 N·m (400 in. lb.)
Pipe Plug (3/4 in.) 28.25 N·m (250 in. lb.)
Rocker Arm Screw 14.6 N·m (130 in. lb.)

Fan/Flywheel

Fan Fastener 9.9 N·m (88 in. lb.)
Flywheel Retaining Screw 67.8 N·m (50 ft . lb.)

Governor Cross Shaft O.D.

Governor Lever Nut 7.3 N·m (65 in. lb.)

Grass Screen

Hex Stud 9.9 N·m (88 in. lb.)
Mounting Screw 9.9 N·m (88 in. lb.)
Front Drive Shaft Screw (into fl ywheel) 24.4 N·m (216 in. lb.)

Ignition

Spark Plug 27 N·m (20 ft. lb.)
Ignition Module Fastener 6.2 N·m (55 in. lb.) into new holes

4.0 N·m (35 in. lb.) into used holes

Lifter Feed Chamber

Cover/Baffl e Screw 6.2 N·m (55 in. lb.)

Muffl er

Retaining Nut 24.4 N·m (216 in. lb.)

Oil Cooler

Mounting Screws 3.9 N·m (35 in. lb.)

Oil Filter

Oil Filter Refer to oil fi lter for instructions.

Oil Filter Adapter/Housing

Mounting Screw 24.4 N·m (216 in. lb.)

Reservoir (oil)

Mounting Screw 24.4 N·m (216 in. lb.)

8 62 690 01 Rev. CKohlerEngines.com

Specifi cations

Torques

CH940 CH960 CH980 CH1000

Solenoid (starter)

Mounting Hardware
Delco-Remy Starter 4.0-6.0 N·m (35-53 in. lb.)

Nut, Positive (+) Brush Lead
Delco-Remy Starter 8.0-11.0 N·m (71-97 in. lb.)

Starter Assembly

Thru Bolt
Delco-Remy (solenoid shift) 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 Starter 2.5-3.3 N·m (22-29 in. lb.)

Stator

Mounting Screw 6.2 N·m (55 in. lb.)

Throttle/Choke Control Bracket

Fastener 9.9 N·m (88 in. lb.)

Valve Cover

Valve Cover Fastener 13.6 N·m (120 in. lb.)

Wear Limits

CH940 CH960 CH980 CH1000

Camshaft

End Play 0.3/1.3 mm (0.011/0.051 in.)
Running Clearance 0.025/0.063 mm (0.0010/0.0025 in.)
Bore I.D.

New
Max. Wear Limit

Bearing Surface O.D.
New
Max. Wear Limit

Cam Lobe Profi le (minimum dimension, measured from base circle
to top of lobe)
Exhaust 35 mm (1.3779 in.)

Intake 34.1 mm

Closure Plate End Main Bearing Journal

O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round

Connecting Rod

Crankpin End I.D. @ 70°F
New
Max. Wear Limit

Connecting Rod-to-Crankpin Running Clearance
New
Max. Wear Limit

Connecting Rod-to-Crankpin Side Clearance 0.30/0.59 mm (0.0118/0.0232 in.)

20.000/20.025 mm (0.7874/0.7884 in.)

20.038 mm (0.7889 in.)

19.962/19.975 mm (0.7859/0.7864 in.)

19.959 mm (0.7858 in.)

35 mm (1.3779 in.)

(1.3425 in.)

44.978/45.00 mm (1.770/1.771 in.)

44.90 mm (1.767 in.)

0.022 mm (0.0009 in.)

0.025 mm (0.0010 in.)

44.030/44.037 mm (1.7334/1.7337 in.)

0.070 mm (0.0028 in.)

0.030/0.055 mm (0.0012/0.0022 in.)

0.070 mm (0.0028 in.)

962 690 01 Rev. C KohlerEngines.com

Specifi cations

Wear Limits

CH940 CH960 CH980 CH1000

Connecting Rod-to-Piston Pin Running Clearance 0.015/0.028 mm (0.0006/0.0011 in.)
Piston Pin End I.D. @ 70°F

New
Max. Wear Limit

Governor Cross Shaft Bore I.D.
New
Max. Wear Limit

Connecting Rod Journal

O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round
Width

Crankcase

Governor Cross Shaft Bore I.D.
New
Max. Wear Limit

Crankshaft

End Play (free) 0.30/1.50 mm (0.011/0.059 in.)
Crankshaft Bore in Closure Plate

New, Without Main Bearing
With Main Bearing Installed
Max. Wear Limit

Crankshaft to Sleeve Bearing (in crankcase)
New, Running Clearance 0.040/0.167 mm (0.0015/0.0065 in.)

Crankshaft Bore (in closure plate)
New, Without Bearing 50.025/50.00 mm (1.9694/1.9685 in.)

Crankshaft to Sleeve Bearing (in closure plate)
New, Running Clearance 0.040/0.167 mm (0.0015/0.0065 in.)

19.023/19.015 mm (0.7489/0.7486 in.)

19.036 mm (0.7494 in.)

8.025/8.050 mm (0.3159/0.3169 in.)

8.088 mm (0.3184 in.)

43.982/44.000 mm (1.731/1.732 in.)

43.97 mm (1.731 in.)

0.018 mm (0.0007 in.)

0.025 mm (0.0010 in.)

53.00/53.09 mm (2.0866/2.0901 in.)

8.025/8.050 mm (0.3159/0.3169 in.)

8.088 mm (0.3184 in.)

50.00/50.025 mm (1.9685/1.969 in.)

45.040/45.145 mm (1.7732/1.7773 in.)

45.158 mm (1.7778 in.)

Crankshaft T.I.R.

PTO End, Crank in Engine 0.279 mm (0.0110 in.)
Entire Crank, in V-Blocks 0.10 mm (0.0039 in.)

Cylinder Bore

Cylinder Bore I.D.
O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round

Cylinder Head

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

Flywheel End Main Bearing Journal

O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round

Governor

Governor Cross Shaft-to-Crankcase Running Clearance 0.025/0.087 mm (0.0009/0.0034 in.)

90.000/90.025 mm (3.543/3.544 in.)

90.075 mm (3.546 in.)

0.013 mm (0.00051 in.)

0.013 mm (0.00051 in.)

44.978/45.00 mm (1.770/1.771 in.)

44.90 mm (1.767 in.)

0.022 mm (0.0009 in.)

0.025 mm (0.0010 in.)

10 62 690 01 Rev. CKohlerEngines.com

Specifi cations

Wear Limits

CH940 CH960 CH980 CH1000

Governor Cross Shaft O.D.

New
Max. Wear Limit

Governor Gear Shaft-to-Governor Gear Running Clearance 0.070/0.160 mm (0.0027/0.0063 in.)
Governor Gear Shaft O.D.

New
Max. Wear Limit

Ignition

Spark Plug Gap 0.76 mm (0.030 in.)
Ignition Module Air Gap 0.28/0.33 mm (0.011/0.013 in.)

Main Bearing I.D. (crankcase/closure plate)

New (installed)
Max. Wear Limit

Piston, Piston Rings, and Piston Pin

Piston-to-Piston Pin Running Clearance 0.006/0.018 mm (0.0002/0.0007 in.)
Piston Pin Bore I.D.

New
Max. Wear Limit

Piston Pin O.D.
New
Max. Wear Limit

Top Compression Ring-to-Groove Side Clearance 0.04/0.08 mm (0.0015/0.0031 in.)
Middle Compression Ring-to-Groove Side Clearance 0.04/0.08 mm (0.0015/0.0031 in.)
Oil Control Ring-to-Groove Side Clearance 0.03/0.19 mm (0.0011/0.0074 in.)
Top and Center Compression Ring End Gap

New
Max. Wear Limit

Piston Thrust Face O.D.

5

New
Max. Wear Limit

Piston Thrust Face-to-Cylinder Bore5 Running Clearance
New 0.033/0.72 mm (0.0013/0.0028 in.)

7.963/8.000 mm (0.3135/0.3149 in.)

7.936 mm (0.3124 in.)

5.990/6.000 mm (0.2358/0.2362 in.)

5.977 mm (0.2353 in.)

45.040/45.145 mm (1.773/1.777 in.)

45.158 mm

19.006/17.013 mm (0.7482/0.7485 in.)

19.025 mm (0.7490 in.)

18.995/19.000 mm (0.7478/0.7480 in.)

18.994 mm (0.7478 in.)

0.30/0.55 mm (0.011/0.021 in.)

0.94 mm (0.037 in.)

89.953/89.967 mm (3.5414/3.5420 in.)

89.925 mm (3.540 in.)

Valves and Valve Lifters

Hydraulic Valve Lift er to Crankcase Running Clearance 0.012/0.050 mm (0.0004/0.0019 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

Exhaust Valve Guide I.D.
New
Max. Wear Limit

Valve Guide Reamer Size
Standard

0.25 mm O.S.
Nominal Valve Face Angle 45°

5

Measure 11 mm (0.433 in.) above bottom of piston skirt at right angles to piston pin.

7.038/7.058 mm (0.2771/0.2779 in.)

7.135 mm (0.2809 in.)

7.038/7.058 mm (0.2771/0.2779 in.)

7.159 mm (0.2819 in.)

7.048 mm (0.2775 in.)

7.298 mm (0.2873 in.)

1162 690 01 Rev. C KohlerEngines.com

Specifi cations

General Torque Values

English Fastener Torque Recommendations for Standard Applications

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

Size Grade 2 Grade 5 Grade 8

Tightening Torque: N·m(in. lb.) + or - 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.) + or - 10%

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) —

Grade 2 or 5 Fasteners

Into Aluminum

Metric Fastener Torque Recommendations for Standard Application

Size

4.8

5.8

Tightening Torque: N·m (in. lb.) + or - 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.) + or - 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)

12 62 690 01 Rev. CKohlerEngines.com

Property Class

8.8

10.9 12.9

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

Noncritical

Fasteners

Into Aluminum

Tools and Aids

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.

Tools
Description Source/Part No.

Alcohol Content Tester

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

Camshaft Endplay Plate

For checking camshaft endplay.

Camshaft Seal Protector (Aegis)

For protecting seal during camshaft installation.

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)

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)

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)

Digital Vacuum/Pressure Tester

For checking crankcase vacuum.
Individual component available:
Rubber Adapter Plug

Electronic Fuel Injection (EFI) Diagnostic Software

For Laptop or Desktop PC.

EFI Service Kit

For troubleshooting and setting up an EFI engine.
Components of 24 761 01-S
Fuel Pressure Tester
Noid Light
90° Adapter
In-line "T" Fitting
Code Plug, Red Wire
Code Plug, Blue Wire
Shrader Valve Adapter Hose

Flywheel Holding Tool (CS)

For holding fl ywheel of CS series engines.

Flywheel Puller

For properly removing fl ywheel from engine.

Flywheel Strap Wrench

For holding fl ywheel during removal.

SE Tools
415 Howard St.
Lapeer, MI 48446
Phone [phone]
Toll Free 800-664-2981
Fax [phone]

Design Technology Inc.
768 Burr Oak Drive
Westmont, IL 60559
Phone [phone]
Fax [phone]

Kohler 25 455 11-S

SE Tools KLR-82405

SE Tools KLR-82417

Kohler 25 761 05-S

Design Technology Inc.

DTI-731-03

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

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

Design Technology Inc.

DTI-721-01

Design Technology Inc.

DTI-721-10

Kohler 25 761 23-S

Kohler 24 761 01-S

Design Technology Inc.

DTI-019
DTI-021
DTI-023
DTI-035
DTI-027
DTI-029
DTI-037

SE Tools KLR-82407

SE Tools KLR-82408

SE Tools KLR-82409

1362 690 01 Rev. C KohlerEngines.com

Tools and Aids

Tools
Description Source/Part No.

Hydraulic Valve Lifter Tool

For removing and installing hydraulic lifters.

Ignition System Tester

For testing output on all systems, including CD.

Inductive Tachometer (Digital)

For checking operating speed (RPM) of an engine.

Offset Wrench (K & M Series)

For removing and reinstalling cylinder barrel retaining nuts.

Oil Pressure Test Kit

For testing/verifying oil pressure on pressure lubricated engines.

Radiator Tester

For pressure testing radiator and cap on Aegis liquid-cooled engines.

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

Spark Advance Module (SAM) Tester

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

.

™

Starter Servicing Kit (All Starters)

For removing and reinstalling drive retaining rings and brushes.
Individual component available:
Starter Brush Holding Tool (Solenoid Shift)

Triad/OHC Timing Tool Set

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

Valve Guide Reamer (K & M Series)

For properly sizing valve guides after installation.

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.

Reamer Handle

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

Valve Guide Service Kit (Courage, Aegis, Command, OHC)

For servicing worn valve guides.

Kohler 25 761 38-S

Kohler 25 455 01-S

Design Technology Inc.

DTI-110

Kohler 52 455 04-S

Kohler 25 761 06-S

Kohler 25 455 10-S

Kohler 25 761 20-S
Kohler 25 761 41-S

Design Technology Inc.

DTI-031
DTI-033

Kohler 25 761 40-S

SE Tools KLR-82411

SE Tools KLR-82416

Kohler 28 761 01-S

Design Technology Inc.

DTI-K828

Kohler 25 455 12-S

Design Technology Inc.

DTI-K830

SE Tools KLR-82415

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
Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S
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. Loctite® Nos. 5900® or 5910® are recommended for best sealing
characteristics.

Spline Drive Lubricant Kohler 25 357 12-S

14 62 690 01 Rev. CKohlerEngines.com

®

51360

Kohler 25 597 07-S

Loctite® 5910

®

Loctite® Ultra Black 598™

Loctite® Ultra Blue 587™

Loctite® Ultra Copper 5920™

Tools and Aids

Flywheel Holding 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.

Rocker Arm/Crankshaft Tool

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.

1562 690 01 Rev. C KohlerEngines.com

Troubleshooting

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 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 plugs.

● Fuel pump malfunction - vacuum hose clogged or

leaking.

● Fuel shut-off valve closed.

● Ignition module 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-SPARKTM 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 plugs.

● 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.

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 plugs.

● Ignition module 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 plugs.

● Idle fuel adjusting needles 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).

16 62 690 01 Rev. CKohlerEngines.com

Troubleshooting

Engine Loses Power

● Dirty air cleaner element.

● Engine overheated.

● Excessive engine load.

● Exhaust restriction.

● Faulty spark plugs.

● 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

indications 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,
over-extended 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 engines, 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 reassembly and placed into operation. Even
small amounts of these cleaners can quickly break down
lubricating properties of engine oil.

1762 690 01 Rev. C KohlerEngines.com

Troubleshooting

Basic Engine Tests

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.

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 of
manometer tubes. 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.

No Crankcase Vacuum/Pressure in Crankcase

Possible Cause Solution

1. Crankcase breather clogged or inoperative. NOTE: Replace valve cover and recheck pressure.

2. Seals and/or gaskets leaking. Loose or improperly
torque fasteners.

3. Piston blowby or leaky valves (confi rm by inspecting
components).

4. Restricted exhaust. 4. Check exhaust screen/spark arrestor (if equipped).

To test crankcase vacuum with Vacuum/Pressure Gauge
Kit:

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, as in step 2, 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 remedies.

Breather is integral part of valve cover and
cannot be serviced separately.

1. Disassemble breather, clean parts thoroughly, check
sealing surfaces for fl atness, reassemble, and
recheck pressure.

2. Replace all worn or damages deals and gaskets.
Make sure all fasteners are tightened securely. Use
appropriate torque valves and sequences when
necessary.

3. Recondition piston, rings, cylinder bore, valves and
valves guides.

Clean or replace as needed. Repair or replace any
other damaged/restricted muffl er or exhaust system
parts.

18 62 690 01 Rev. CKohlerEngines.com

Troubleshooting

Compression Test

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 command twins)

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 disconnect for attaching adapter hose and a holding tool.

Leakdown Test Instructions

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 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 increase (clockwise) 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.

Leakdown Test Results

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.

1962 690 01 Rev. C KohlerEngines.com

Air Cleaner/Intake

These systems are CARB/EPA certifi ed and components
should not be altered or modifi ed in any way.

Low-Profi le Air Cleaner

B

C

D

E

A

A Element Latch B Cover Knobs
C Air Cleaner Cover D Precleaner

E Element

Heavy-Duty Air Cleaner

G

H

J

I

K

F

Air Cleaners

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

Loosen knobs and remove air cleaner cover.
Precleaner:

1. Remove precleaner from paper element.

2. 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. Rotate element latch (if equipped); remove paper
element with precleaner.

2. Separate precleaner from element; service
precleaner and replace paper element.

3. Install new paper element on base; install precleaner
over paper element; rotate element latch
(if equipped).

Reinstall air cleaner cover and secure with knobs.

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.

F Air Cleaner Housing G End Cap
H Element I Inner Element
J Ejector Area K Inlet Screen

Breather Tube

Make 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. See Maintenance Schedule.

62 690 01 Rev. CKohlerEngines.com20

Fuel System and Governor

Typical carbureted fuel system and related components include following:

● Fuel Tank and Valve ● In-line Fuel Filter ● Carburetor

● Fuel Lines ● Fuel Pump

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.

Keihin BK Two-Barrel Carburetor - Exploded View

D

E

F

G

B

AF

C

H

AB

AA

I

AC

AD

Z

AE

U

T

Q

V

X

Carburetor Body

A

Subassembly

F
K

P Sealing Washer Q Float R Pin S Screw T Float Clip
U
Z Choke Dust Cap AA Choke Shaft AB Spring AC Bushing AD Choke Lever

AE Choke Plate AF

Retaining

Washer

O-ring (Fuel

Bowl - Upper)

Float Valve/

Inlet Needle

Y

B
G

L

V

W

Idle Speed

Screw

Slow Jet -

RH Side

O-ring (Fuel

Bowl Lower)

Main Nozzle -

Right Side

Choke Plate

Screw (2)

S

C
H
M Drain Screw N Bowl Screw (4) O Fuel Solenoid

W

Idle Speed

Main Nozzle -

A

K

R

M

Spring

Slow Jet -

LH Side

Left Side

L

J

N

P

O

D Screw E Ground Lead

I

X

O-ring

(Slow Jet) (2)

Main Jet -

Right Side

J Fuel Bowl

Y

Main Jet -

Left Side

2162 690 01 Rev. C KohlerEngines.com

Fuel System and Governor

Fuel Recommendations Fuel Line

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; effects 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.

Low permeation fuel line must be installed on carbureted
Kohler Co. engines to maintain EPA and CARB
regulatory compliance.

Fuel Pump

These engines use either a mechanical fuel pump, or
optional remote-mounted electric fuel pump assembly.
Operation of mechanical fuel pump occurs by direct
lever/pump actuation off rocker arm movement. 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, internal check valves prevent fuel from
going backward through pump.

Fuel Pump Replacement

Mechanical fuel pump is an integral part of valve cover
assembly and not serviced separately.

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

2. Follow procedure for replacing valve cover.

3. Reconnect fuel lines to inlet and outlet fi ttings and
secure with clamps.

Fuel System Tests

When the engine starts hard, or turns over but will not start, it is possible that the problem is in the fuel system. To fi nd
out if the fuel system is causing the problem, perform the following test.

Troubleshooting -- Fuel System Related Causes

Test Conclusion

Check for fuel in combustion chamber.

1. 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.

Check for fuel fl ow from tank to fuel pump.

2. a. Remove fuel line from inlet fi tting of fuel pump.
b. Hold line below bottom of tank. Open shut-off

valve (if so equipped) and observe fl ow.

Check operation of fuel pump.

3. a. Remove fuel line from inlet fi tting of carburetor.
b. Crank engine several times and observe fl ow.

1. If there is fuel at tip of spark plug, fuel is reaching
combustion chamber.

If there is no fuel at tip of spark plug, check for fuel

fl ow from fuel tank (step 2).

2. If fuel does fl ow from line, check for faulty fuel pump
(step 3).

If fuel does not fl ow from 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.

3. If fuel does fl ow from line, check for faulty carburetor.

If fuel does not fl ow from line, check for a clogged

fuel line. If fuel line is unobstructed, check for
overfi lled crankcase and/or oil in pulse line. If none of
checks reveal cause of problem, replace pump.

22 62 690 01 Rev. CKohlerEngines.com

Fuel System and Governor

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.

Engines in this series are equipped with a Keihin BK
two-barrel, side-draft carburetor with fi xed main jets on a
matching intake manifold. Carburetor features a self­relieving choke, serviceable slow jets, main jets, bowl
drain and a fuel shutdown solenoid.

Troubleshooting -- Carburetor Related Causes

Condition Probable Cause/Probable Remedy

1. Engine starts hard, runs roughly, or stalls at idle
speed.

2. Engine runs rich (indicated by black, sooty exhaust
smoke, misfi ring, loss of speed and power, governor
hunting, or excessive throttle opening).

3. Engine runs lean (indicated by misfi ring, loss of
speed and power, governor hunting, or excessive
throttle opening).

4. Fuel leaks from carburetor. 4 a. Float level set too high. See Remedy 2d.

Troubleshooting Checklist

When engine starts hard, runs roughly, or stalls at low
idle speed, check following areas before adjusting or
disassembling carburetor.

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

● Make sure fuel tank cap vent is not blocked and that
it is operating properly.

● 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.

● Make sure air cleaner base and carburetor are
securely fastened to engine using gaskets in good
condition.

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

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

1. Low idle fuel mixture (some models)/speed
improperly adjusted. Adjust low idle speed tab, then
adjust low idle fuel needle.

2 a. Clogged air cleaner. Clean or replace.
b. Choke partially closed during operation. Check

choke lever/linkage to ensure choke is operating
properly.

c. Low idle fuel mixture is improperly adjusted.

Adjust low idle fuel needle (some models).

d. Float level is set too high. Adjust fl oat according

to Float Replacement Procedure.

e. Dirt under fuel inlet needle. Remove needle;

clean needle and seat and blow with compressed
air.

f. 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.

g. Leaky, cracked or damaged fl oat. Submerge fl oat

to check for leaks.

3 a. Low idle fuel mixture is improperly adjusted. See

Remedy 2c.
b. Float level is set too low. See rememdy 2d.
c. 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.

b. Dirt under fuel inlet needle. See Remedy 2e.
c. Bowl vents plugged. Blow out with compressed

air.
d. Carburetor bowl gasket leaks. Replace gasket.

2362 690 01 Rev. C KohlerEngines.com

Fuel System and Governor

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 jets. When current is
removed pin extends blocking fuel fl ow.

Below is a simple test, made 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 it off
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.

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 & 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 two main jets and further
metered through slow jets. Air and fuel are mixed in
body of slow jet and exit to transfer port. From transfer
port air fuel mixture is delivered to idle progression
chamber. From idle progression chamber air fuel mixture
is metered through idle port passages. At low idle when
vacuum signal is weak, 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 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 four air jets,
fuel is drawn through main jets. Air and fuel are mixed in
main nozzles and then enter 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. To ensure best results
when setting low idle fuel needle, low idle speed
should be 1200 RPM (± 75 RPM).

Low Idle Speed (RPM) Setting:

1. Place throttle control in idle or slow position.

2. Set low idle speed approximately 300 RPM less than
intended or specifi ed Governed Idle Speed, by
turning low idle speed adjusting screw in or out.

3. Check speed using a tachometer.

IMPORTANT: Governed Idle Speed Adjustment must

follow any resetting of Low Idle Speed.

4. If equipped, refer to Governed Idle Speed
Adjustment.

Low Idle Fuel Adjustment

Adjust to
Midpoint

Rich

Lean

Left Side

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

on two idle fuel adjusting needles. Step 3 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 Adjusting Low
Idle Speed (RPM) procedure.

2. Low Idle Fuel Needle(s) Setting: place throttle into
idle or slow position.

a. Turn one 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.

3. Recheck/adjust Low Idle Speed (RPM) to specifi ed
setting.

Adjust to
Midpoint

Rich

Right Side

Lean

24 62 690 01 Rev. CKohlerEngines.com

Fuel System and Governor

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 side 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.

Float Replacement/Overhaul/Choke Repair

NOTE: Inlet needle center pin is spring loaded. Make

sure fl oat rests against fuel inlet needle without
depressing center pin.

If symptoms described in carburetor troubleshooting
guide indicate fl oat level problems, remove carburetor
from engine to check and/or replace fl oat. Use a fl oat kit
to replace fl oat, pin, fl oat valve, clip, and screw.

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 four
mounting screws 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/removal of bowl
drain screw.

3. Remove fl oat pin screw and lift out old fl oat, pin and

inlet needle. Discard all of parts. Seat for inlet needle
is not serviceable, and should not be removed.

4. Clean carburetor bowl and inlet seat areas as

required, before installing new parts.

To service carburetor further, continue following

overhaul procedure. Otherwise skip to step 23 to
reassemble the fuel bowl.

5. Carefully remove two main jets from carburetor. Note

and mark jets by location for proper installation. Main
jets may be size/side specifi c. After main jets are
removed, main nozzles can be removed out through
bottom of main towers. Note orientation/direction of
nozzles. End with two raised shoulders should be
out/down adjacent to main jets. Save parts for
cleaning and reuse.

6. Remove screw securing fl at washer and ground lead
(if equipped), from top of carburetor; then carefully
pull (lift) out two slow jets. Slow jets may be sized/
side specifi c. 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.

7. Remove idle speed (RPM) adjustment screw and
spring from carburetor. Discard parts.

Carburetor is now disassembled for appropriate

cleaning and installation of parts in overhaul kit.
Further disassembly is not necessary. Throttle shaft
assembly, fuel inlet seat, idle fuel adjustment screws
with limiter, and carburetor body, are non-serviceable
items and should not be removed. Choke shaft
assembly is serviceable, however it should not be
removed unless a Choke Repair Kit will be installed.

To service the choke shaft, continue following

overhaul procedure. Otherwise skip to step 18.

8. Remove and discard plastic cap from end of choke
lever/shaft assembly.

9. Note position of spring legs and choke plate for
correct reassembly later. Remove two screws
attaching choke plate to choke shaft. Pull shaft out of
carburetor body, note preload of spring and discard
removed parts.

10. Use a screw extractor (easy-out) and remove
original choke shaft bushing with old choke lever
from carburetor housing. Save bushing to use as a
driver for installing new bushing. Discard old lever.

11. Clean I.D. of both choke shaft bores as required.

12. Insert new bushing through new choke lever from
outside, and start bushing in outer shaft bore.
Position choke lever so protruding boss on
carburetor housing is between two stops formed in
choke lever.

13. Turn old bushing upside down and use it as a driver
to carefully press or tap new bushing into carburetor
body until it bottoms. Check that choke lever pivots
freely without restriction or binding.

14. Install new return spring onto new choke shaft, so
outboard leg of spring is behind formed stop on end
of choke shaft.

Make sure it stays in this location during following

step.

15. Slide choke shaft and spring into carburetor. Pivot
(preload) shaft 3/4 turn counterclockwise with inner
leg of spring against formed stop within choke lever
as originally assembled. Outer leg of spring must still
be behind formed stop of choke shaft.

16. Place a drop of Loctite® 222MS™ on threads of
each new screw. Position and install new choke
plate to fl at side of choke shaft. Start two screws.
Close choke and check plate alignment within
carburetor throat, then tighten screws securely. Do
not overtighten.

17. Check for proper operation and free movement of
parts. Install new cap.

2562 690 01 Rev. C KohlerEngines.com

Fuel System and Governor

Always use new gaskets when servicing or reinstalling
carburetors. Repair kits are available which include
new gaskets and other components. Service/repair
kits available for Keihin BK two-barrel carburetors and
affi liated components are:

18. Clean carburetor body, main jets, vent ports, seats,
etc., using a good commercially available carburetor
solvent. Keep away from plastic or rubber parts if
non-compatible. Use clean, dry compressed air to
blow out internal channels and ports. Do not use
metal tools or wire to clean orifi ces and jets. Inspect
and thoroughly check carburetor for cracks, wear, or
damage. Inspect fuel inlet seat for wear or damage.
Check spring loaded choke plate to make sure it
moves freely on shaft.

19. Install two main nozzles into towers of carburetor
body. End of main nozzles with two raised shoulders
should be out/down (adjacent to main jets). Make
sure nozzles are completely bottomed. Carefully
install main jets into towers of carburetor body on
appropriate side, as identifi ed when removal was
performed.

20. Make sure O-ring near bottom of each slow jet is
new, or in good condition. Align and insert two slow
jets into top of carburetor.

21. Install large fl at retaining washer and secure with
mounting screw, attaching ground lead if originally
secured by screw.

22. Install new idle speed (RPM) adjustment screw and
spring onto carburetor. Thread in until 3 or 4 threads
are exposed, as an initial adjustment.

23. Attach inlet needle to plastic tang of fl oat with wire
clip. Formed 90° lip should point up, with needle
valve hanging down.

24. Install fl oat and inlet needle down into seat and
carburetor body. Install new pivot pin through fl oat
hinge and secure with new retaining screw.

25. Hold carburetor body so fl oat assembly hangs
vertically and rests lightly against fuel inlet needle.
Inlet needle should be fully seated but center pin of
needle (on retainer clip end) should not be
depressed. Check fl oat height adjustment.

Be sure to measure from casting surface, not rubber

gasket, if still attached.

26. Correct fl oat height setting is 17 mm (0.669 in.) ± 1.5
mm (0.059 in.), measured from fl oat bottom to body
of carburetor. Replace fl oat if height is different than
specifi ed. DO NOT attempt to adjust by bending fl oat
tab.

27. When proper fl oat height is obtained, carefully
reinstall fuel bowl onto carburetor, using new
O-rings. Secure with four original screws. Tighten
screws to torque specifi cations.

28. Set the two idle mixture screws at the midpoint of
available adjustment as a preliminary setting.

29. Use the new mounting gaskets provided for the air
cleaner and carburetor. Reinstall the carburetor and
disassembled components following Reassembly
procedures.

30. Reconnect the spark plug leads and negative battery

cable. Start the engine and perform Low Idle Speed
and Low Idle Fuel Needle(s) settings as outlined in

the service manual.

High Altitude Operation

This engine may require a high altitude carburetor
kit to ensure correct engine operation at altitudes
above 1219 meters (4000 ft.). To obtain high
altitude 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 1219 meters (4000 ft.) as damage
may occur if high altitude carburetor kit is installed and
operated below 1219 meters (4000 ft.).

Governor

Governed speed setting is determined by position of
throttle control. It can be variable or constant, depending
on engine application.

Governor is designed to hold engine speed constant
under changing load conditions. Most engines are
equipped with a centrifugal fl yweight mechanical
governor. Governor gear/fl yweight mechanism of
mechanical governor is mounted inside crankcase and is
driven off gear on camshaft. This governor design 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 throttle 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 arm 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
offset each other to hold a steady engine speed.

26 62 690 01 Rev. CKohlerEngines.com

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 hex 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 clockwise (viewed from end) as far
as it will turn, then tighten hex nut to torque
specifi cations.

Governed Idle Speed Adjustment

1. Make sure governed idle spring is in outer hole in
governor lever and hole in governed idle (outer)
adjuster.

2. Make sure governor spring is in inner slot of
governor lever and hole in high speed (inner)
adjuster. Pull governor lever away from carburetor to
limit of its travel and check that governor spring is
loose and not under any tension. Turn high-speed
(RPM) adjustment screw counter-clockwise
(if required) until spring is loose.

3. 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 using a tachometer. Turn adjustment screw
(inner) clockwise (in) to increase or counterclockwise
(out) to decrease speed.

4. Release governor lever and check that throttle lever
is in idle (centered) position. Turn governed idle
(outer) adjustment screw to obtain equipment
manufacturer’s recommended idle speed
(1500-1800 RPM). Governed idle speed (RPM) is
typically 300 RPM (approximate) higher than low idle
speed.

5. Move throttle lever to wide-open/full throttle position
and hold in this position. Check RPM using a
tachometer. Turn high speed screw to obtain
intended high speed no-load RPM. Governed idle
speed must be set before making this adjustment.

High Speed (RPM) Adjustment

1. With engine running, move throttle control to fast.
Use a tachometer to check RPM speed.

2. Turn inner adjustment screw outward to decrease, or
inward to increase RPM speed. Check RPM with a
tachometer.

3. Stop when desired RPM speed is obtained.

Fuel System and Governor

2762 690 01 Rev. C KohlerEngines.com

Lubrication System

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. Closure plate must be removed to service
oil pickup, pressure relief valve, and oil pump.

A

B

C

D

A Oil Filter B Under Side C Top Side D Oil Cooler E Cylinder Shroud
F Oil Drain Plug G Oil Fill Cap H Dipstick I Pressure Switch

Oil Recommendations

We recommend use of Kohler oils for best performance.
Other high-quality detergent oils (including synthetic)
of API (American Petroleum Institute) service class SJ
or higher are acceptable. Select viscosity based on
air temperature at time of operation as shown in table
below.

G

E

Check Oil Level

NOTE: To prevent extensive engine wear or damage,

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

1. Remove dipstick; wipe oil off.
a. Press-in cap: reinsert dipstick into tube; press

completely down.

b. Thread-on cap: reinsert dipstick into tube; rest

cap on tube, do not thread cap onto tube.

2. Remove dipstick; check oil level. Level should be at
top of indicator on dipstick.

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

4. Reinstall and secure dipstick.

H

F

never run engine with oil level below or above
operating range indicator on dipstick.

or

I

28 62 690 01 Rev. CKohlerEngines.com

Lubrication System

Change Oil and Oil Filter

Change oil while engine is warm.

1. Clean area around oil fi ll cap/dipstick and drain plug.
Remove drain plug and oil fi ll cap/dipstick. Allow oil
to drain completely.

2. Clean area around oil fi lter; remove fi lter; wipe off
mounting surface. Reinstall drain plug. Tighten to
torque specifi cations.

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.

Service Oil Cooler

NOTE: Oil cooler is mounted under cylinder shroud.

Removal of cylinder shroud is necessary to
access oil cooler.

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

2. Remove two screws securing oil cooler, and tilt to
clean back side.

3. Reinstall oil cooler.

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 port. On engines not equipped with Oil Sentry™

pressure switch is installed in closure plate

™

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

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 closure plate.

3. Tighten switch to torque specifi cations.

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 7-11 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 7-11
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.

2962 690 01 Rev. C KohlerEngines.com

Electrical System

Spark Plugs

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: Refer to specifi cations.

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.

Spark Plug Service

Clean out spark plug recess. Remove plug and replace.

1. Check gap using wire feeler gauge. Adjust gap, see
specifi cation table for adjustment.

2. Install plug into cylinder head.

3. Torque plug to specifi cations.

A

B

C

A Wire Gauge B Spark Plug
C Ground Electrode D Gap

D

30 62 690 01 Rev. CKohlerEngines.com

Electrical System

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

A plug taken from an engine
operating under normal conditions
will have light tan or gray colored
deposits. If center electrode is not
worn, a plug in this condition could
be set to proper gap and reused.

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.

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.

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.

Carbon Fouled

Soft, sooty, black deposits indicate
incomplete combustion caused by
a restricted air cleaner, over rich
carburetion, weak ignition, or poor
compression.

3162 690 01 Rev. C KohlerEngines.com

Electrical System

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 also to operating instructions of equipment this
engine powers for specifi c battery requirements.

Electronic Ignition Systems

There are two different types of ignition systems used on these engines. All systems use an ignition module which
energizes spark plug. Difference in system is in way ignition timing is triggered.

Fixed Ignition System

This engine uses a capacitive discharge (CD) coil where 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 top dead
center. A typical fi xed ignition system consists of:

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

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

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

● Two spark plugs.

Battery Size Recommendations

Temperature Battery Required

Above 32°F (0°C) 300 cca minimum

0°F to 32°F (-18°C to 0°C) 300 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.

Digital Spark Advance Ignition (DSAI) System

This system uses a digital microprocessor which is located in ignition modules. Ignition timing varies depending upon
engine speed with this system. Two inductive-style ignition modules control ignition timing based on engine RPM. A
typical DSAI application consists of:

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

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

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

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

● Two spark plugs.

Both 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.

32 62 690 01 Rev. CKohlerEngines.com

Electrical System

Troubleshooting CD Ignition Systems

NOTE: CD ignition systems are sensitive to excessive load on kill lead. If a customer complains of hard starting, low

power, or misfi re under load, it may be due to excessive draw on kill circuit. Perform appropriate test
procedure.

Isolate and verify trouble is within engine ignition system.

Troubleshooting -- CD Ignition Systems

Test Conclusion

1. Locate plug 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.

2. Test for spark on both cylinders with Kohler ignition
tester. Disconnect one spark plug lead and connect
it to post terminal of tester. Connect clip to a good
ground, not to spark plug.

Crank engine and observe tester spark gap. Repeat

procedure on other cylinder. Remember to reconnect
fi rst spark plug lead.

1. If problem is gone, electrical system on unit is
suspect. Check key switch, wires, connections,
safety interlocks, etc.

If problem persists, condition is associated with

ignition or electrical system of engine. Leave kill lead
isolated until all testing is completed.

2. If one side is not fi ring, check all wiring, connections,
and terminations on that side. If wiring is okay,
replace ignition module and retest for spark.

If tester shows spark, but engine misses or won’t run

on that cylinder, try a new spark plug.

If neither side is fi ring, recheck position of ignition

switch and check for shorted kill lead.

Test Procedure for DSAI Ignition Systems

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 making any of these 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.

F

A

B

C

Kill Switch/

A
C Flywheel D Magnet

E Ignition Modules F Spark Plug

Off Position of

Key Switch

B Air Gap

D

E

3362 690 01 Rev. C KohlerEngines.com

Electrical System

Troubleshooting -- Electric Ignition System

Test Conclusion

Check Ignition System
NOTE: If engine starts or runs during any of 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.

Test for Spark
NOTE: If two testers are available, testing can be performed

simultaneously for both cylinders. However, if only one
tester is available, two 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 one spark plug lead disconnected
and not grounded, or permanent system damage may
occur.

1. With engine stopped, disconnect one 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 550-600
RPM, and observe tester(s) for spark.

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

Check for Timing Advance

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.

Test Ignition Modules and Connections

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.

If problem goes away, electrical system on
equipment is suspect. Check key switch, wires,
connections, safety interlocks, etc.

If problem persists, condition is associated with
ignition or electrical system of engine. 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 affected,
test ignition modules and connections but also
check white kill lead connection for affected DSAI
module.

If both cylinders have good spark but engine runs
poorly, or existing plug condition or appearance is
questionable, install new spark plugs, and retest
engine performance. If problem persists, check for
timing advance.

If one cylinder had good spark but other cylinder
had no spark, or intermittent spark, test ignition
modules and connections.

If there was spark on both cylinders but power is
suspect, check for timing advance.

If line on screen moved away from line on blower
housing during acceleration, DSAI ignition module
for cylinder being tested is working properly. If
it didn’t move away, test ignition modules and
connections.

If you were able to check timing on both cylinders,
lines you made on blower housing should be
90° apart. If not, test ignition modules and
connections.

If all tests are OK and module has no spark or
fails to advance, replace affected module.

If any of tests are bad; determine cause and fi x as
required, then retest.

34 62 690 01 Rev. CKohlerEngines.com

Electron CD Fixed Ignition Timing System

Electrical System

Digital Spark Advance Ignition (DSAI) System

BLUE WIRE

WHITE WIRES

BATTERY

B-BATTERY

A-ACCESSORY

GROUND

RED WIRES

CONNECTOR, 5-CIRCUIT

NEG.

RED

FUSE

BLUE

YELLOW WIRES

BLACK WIRE

RED WIRE

CONNECTOR, 1-CIRCUIT
(ACCESSORY)

YELLOW (ACCESSORY) (+)

GREEN
(OIL SENTRY PULSE SIGNAL)
(NOT VALID WITH INDICATOR
LIGHT OR NO PRESSURE SWITCH)

WHITE
(ALTERNATIVE IGNITION
PULSE SIGNAL) (-)

VIOLET (B+ LEAD)

SWITCH, KEY

STARTER

M-MAGNETO

R-RECTIFIER

STARTER ASSEMBLY

POS.

STARTER
SOLENOID
STUD

STARTER
SOLENOID
TANG

YELLOW

RED

WHITE

OIL SENTRY
LIGHT

REGULATOR
RECTIFIER

CARB.
SOLENOID

BLACK

REGULATOR
CONNECTOR
BLOCK

WHITE
(AC CHARGING
LEADS)

LIGHT ASSEMBLY, INDICATOR
(OPTIONAL)

OIL PRESSURE SWITCH
(OPTIONAL)

BLACK

RED

RED

CARB MOUNTING
STUD

GROUND

CARB.

FLYWHEEL
STATOR
ASS’Y

RED

GREEN
(NOT VALID WITH INDICATOR
LIGHT OR NO PRESSURE SWITCH)

SPARK PLUG
#1 CYLINDER

IGNITION
(MODULES)

MODULE
MTG SCREW

GROUND

SPARK PLUG
#2 CYLINDER

(SPARK PLUG LEAD)

BLACK
(GROUD)

MODULE LEAD
DESIGNATION

RED
(B+)

WHITE
(SHUT OFF)

3562 690 01 Rev. C KohlerEngines.com

Electrical System

Wire Diagram-15/20/25 Amp Regulated Battery Charging System with Fixed Timing, Four Pin Connector

36 62 690 01 Rev. CKohlerEngines.com

Electrical System

Wire Diagram-15/20/25 Amp Regulated Battery Charging System with Fixed Timing, Five Pin Connector, Key
Switch, and Fuse.

3762 690 01 Rev. C KohlerEngines.com

Electrical System

Wire Diagram-15/20/25 Amp Regulated Battery Charging System with DSAI Ignition, Five Pin Connector and
Key Switch

38 62 690 01 Rev. CKohlerEngines.com

Electrical System

Wire Diagram-15/20/25 Amp Regulated Battery Charging System with DSAI Ignition and Four Pin Connector
(LP-NG Kohler Power Systems Application)

3962 690 01 Rev. C KohlerEngines.com

Electrical System

Wire Diagram-15/20/25 Amp Regulated Battery Charging System with DSAI Ignition and Five Pin Connector
(Gasoline/LP-NG Non-Kohler Power Systems Application)

40 62 690 01 Rev. CKohlerEngines.com

Electrical System

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. Also, 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.

NOTE: 20 amp charging systems use a 15 amp stator with a 25 amp rectifi er-regulator.
Most engines are equipped with a 15, 20, or 25 amp regulated charging system.

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 positions and install plug correctly.
Rectifi er-regulator is mounted on backing shroud assembly. To replace it, disconnect plug, remove two mounting

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

To Test

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

regulator mounted or loose. Figures show part removed from engine for clarity. Repeat applicable test
procedure two or three times to determine condition of part.

20/25 Amp Rectifi er-Regulators 15 Amp Rectifi er-Regulators

*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.

1. Connect single lead adapter in between B+ (center)

terminal of rectifi er-regulator being tested and
squared single end of tandem adapter lead.

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

body of rectifi er-regulator.

3. Connect red lead and one of black leads 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 one of

outer AC terminals 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 one of four 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 one of four lights will illuminate
indicating partial condition of part.

a. If OK (green) light comes on, disconnect tester

black lead attached to one 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.

b. If any other light is displayed* in either of tests,

rectifi er-regulator is faulty and should not 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.

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 two black tester leads to two AC
terminals.

3. Plug tester into proper AC outlet/power for tester
being used. Turn on power switch. POWER light
should be illuminated and one of four status lights
may be on as well. This does not represent condition
of part.

4. Press TEST button until a click is heard and then
release. Momentarily one of four status lights will
illuminate, indicating condition of part.

a. If OK (green) light comes on and stays steady,

part is good and may be used.

b. If any other light is displayed,* rectifi er-regulator

is faulty and should not be used.

4162 690 01 Rev. C KohlerEngines.com

Electrical System

Troubleshooting Guide

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

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

15/20/25 Amp Battery Charging Systems

When problems occur in keeping battery charged or battery charges at too high a rate, problem can usually be found
somewhere in charging system or with battery.

Problem Test Conclusion

No Charge

to Battery

Battery

Continuously

Charges at

High Rate

*NOTE: Turn on lights, if 60 watts or more. Or

place a 2.5 ohm, 100 watt resistor
across battery terminals.

1. Trace B+ lead from rectifi er-regulator to key
switch, or other accessible connection.
Disconnect it from switch or connection.
Connect an ammeter from loose end of B+
lead to positive terminal of battery. Connect
DC voltmeter from loose end of B+ lead to
negative terminal of battery. With engine
running at 3600 RPM, read voltage on
voltmeter.

If voltage is 13.8 volts or more, place a

minimum load of 5 amps* on battery to
reduce voltage. Observe ammeter.

2. Remove connector from rectifi er-regulator.
With engine running at 3600 RPM, measure
AC voltage across stator leads using an AC
voltmeter.

3 a. With engine stopped, measure

resistance across stator leads using an
ohmmeter.

b. With engine stopped, measure

resistance from each stator lead to
ground using an ohmmeter.

4. Perform same test as Step 1 above. 4. If voltage is 14.7 volts or less charging

1. If voltage is 13.8-14.7 and charge rate
increases when load is applied, charging
system is OK and battery was fully charged.

If voltage is less than 13.8 or charge rate

does not increase when load is applied,
check regulator-rectifi er ground. Adequate
ground is required for regulator-rectifi er to
operate. If ground path is good, test stator
(tests 2 and 3).

2. If voltage is 28 volts or more, stator is OK.
Rectifi er-regulator is faulty. Replace
rectifi er-regulator.

If voltage is less than 28 volts, stator is

probably faulty and should be replaced. Test
stator further using an ohmmeter (test 3).

3 a. If resistance is 0.064/0.2 ohms, stator is

OK.

If resistance is infi nity ohms, stator is

open. Replace stator.

b. If resistance is infi nity ohms (no

continuity), stator is OK (not shorted to
ground).

If resistance (or continuity) is measured,

stator leads are shorted to ground.
Replace stator.

system is OK. Battery is unable to hold a
charge. Service battery or replace as
necessary.

If voltage is more than 14.7 volts, rectifi er-

regulator is faulty. Replace rectifi er-
regulator.

42 62 690 01 Rev. CKohlerEngines.com

Electrical System

Electric Starting Motors

Engines in this series use solenoid shift starters. A Delco-Remy solenoid shift starter is typically used.

Starting Motor Precautions

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, resulting in damage to 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.

Starter Removal and Installation

Refer to disassembly and reassembly for starter removal and installation procedures.

Operation – Solenoid Shift Starter

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.

Troubleshooting Guide – Starting Diffi culties

Problem Possible Fault Correction

1. Check specifi c gravity of battery. If low, recharge or replace battery as
necessary.

1. Clean corroded connections and tighten loose connections.

2. Replace wires in poor condition and with frayed or broken insulation.

1. By-pass switch or solenoid with a jumper wire. If starter cranks normally,
replace faulty components. Remove and perform individual solenoid test
procedure.

1. Check specifi c gravity of battery. If low, recharge or replace battery as
necessary.

1. Check for excessively dirty or worn brushes and commutator. Clean
using a coarse cloth (not emery cloth).

2. Replace brushes if excessively or unevenly worn.

1. 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.

2. Check for seized engine components such as bearings, connecting rod,
and piston.

Starter

Does Not

Energize

Starter

Energizes

but Turns

Slowly

Battery

Wiring

Starter Switch

or Solenoid

Battery

Brushes

Transmission

or

Engine

4362 690 01 Rev. C KohlerEngines.com

Electrical System

Delco-Remy Starters

H

G

F

E

D

C

B

A

Starter Disassembly

NOTE: Test procedure for checking starter solenoid.

I

J

K

L

M

M

O

P

Q

R

S

T

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.

1. Remove hex nut and disconnect positive (+) brush
lead/bracket from solenoid terminal.

2. Remove three Torx head screws securing solenoid
to starter.

3. Unhook plunger pin from drive lever. Remove gasket
from recess in housing.

4. Remove two 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.

U

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

S
U Bolt

Plate

T

Screw

44 62 690 01 Rev. CKohlerEngines.com

Electrical System

Inspection
Drive Pinion

Check and inspect following areas:
a. Pinion teeth for abnormal wear or damage.
b. Surface between pinion and clutch mechanism

for nicks, or irregularities which could cause seal
damage.

c. Check drive clutch by holding clutch housing and

rotating pinion. Pinion should rotate in one
direction only.

Brushes and Springs

B

A

D

E

A Wear Limit Length B Commutator O.D.
C Mica Insulation D Insulation Check
E Armature Coil F Continuity Check

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 their condition is
questionable.

Armature

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 two different 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
two, armature is bad.

4. Check armature windings/insulation for shorting.

C

F

Shift Fork

Check that shift fork is complete, and pivot and contact
areas are not excessively worn, cracked, or broken.

Brush Replacement

Brushes and springs are serviced as a set (4). Use
a new Kohler Brush and Spring Kit, if replacement is
necessary.

1. Perform Steps 1-5 in Starter Disassembly.

2. Remove two 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 Service

Clean drive lever and armature shaft. Apply Kohler
electric starter drive lubricant (Versilube G322L or Mobil
Temp SHC 32) to lever and shaft. Clean and check other
starter parts for wear or damage as required.

Starter Reassembly

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

retainers which have been removed.

NOTE: Correctly installed, center pivot section of drive

lever will be fl ush or below machined surface of
housing which receives backup washer.

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 offset thrust (stop) washer so smaller offset 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.

4562 690 01 Rev. C KohlerEngines.com

Electrical System

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 over each of brush assemblies. Do not lose springs.
b. Position each of 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 four 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 two thru bolts, and two brush holder mounting screws. Tighten bolts to torque specifi cations. Tighten brush

holder mounting screws to torque specifi cations.

13. Hook plunger behind upper end of drive lever, and install spring into solenoid. Insert three mounting screws

through holes in drive end cap. Use these to hold solenoid gasket in position, then mount solenoid. Tighten
screws to torque specifi cations.

14. Connect positive (+) brush lead/bracket to solenoid and secure with hex nut. Tighten nut to torque specifi cations.

Do not overtighten.

Solenoid Test Procedure
Solenoid Shift Style Starters

Disconnect all leads from solenoid including positive brush lead attached to lower stud terminal. Remove mounting
hardware and separate solenoid from starter for testing.

Test 1 Solenoid Pull-In Coil/Plunger Actuation Test

*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 otherwise occur.

Use a 12 volt power supply and two test leads. Connect
one 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. If solenoid fails to activate, it should be replaced.

Test 3 Solenoid Hold-In Coil Function Test

Connect one 12 volt test lead to fl at spade S/start
terminal on solenoid, and other lead to body or mounting
surface of solenoid. Then, manually push plunger In
and check if Hold-In coil holds plunger retracted. Do
not allow test leads to remain connected to solenoid
for a prolonged period of time. If plunger fails to stay
retracted, solenoid should be replaced.

Test 2 Solenoid Pull-In Coil/Contact Continuity Test

Use an ohmmeter set to audible or Rx2K scale, and
connect two ohmmeter leads to two large post terminals.
Perform preceding test (1) and check for continuity.
Ohmmeter should indicate continuity, if no continuity
is indicated solenoid should be replaced. Repeat test
several times to confi rm condition.

Test 4 Solenoid Hold-In Coil/Contact Continuity Test

Use an ohmmeter set to audible or Rx2K scale, and
connect two ohmmeter leads to two large post terminals.
Perform preceding test (3) and check for continuity.
Meter should indicate continuity. If no continuity is
indicated, solenoid should be replaced. Repeat test
several times to confi rm condition.

46 62 690 01 Rev. CKohlerEngines.com

WARNING

Accidental Starts can cause severe injury or
death.

Disconnect and ground spark plug lead(s)
before servicing.

U

V

U

A

B

Disassembly

Before working on engine or equipment, disable engine as
follows: 1) Disconnect spark plug lead(s). 2) Disconnect
negative (–) battery cable from battery.

Heavy-Duty Air Cleaner

T

U

C

D

E

F

S

R

P

Q

V

P

G

H

I

O

J

H

L

K

Low-Profi le
Air Cleaner

I

M

L

A Oil Filter B Oil Filter Nipple C Oil Filter Cup D Valve Spring

E Cup Spring F Valve G Oil Filter Housing H Valley Baffl e

I Outer Cylinder Baffl e J Electric Starter K Backing Shroud L Cylinder Shroud
M Blower Housing N Guard O Oil Sentry
Q Pin R Fitting S Oil Filter Adapter T Oil Cooler
U Hose V Hose Clamp

N

™

P O-ring

4762 690 01 Rev. C KohlerEngines.com

Disassembly

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.

Disconnect leads from spark plugs.

Drain Oil from Crankcase and Remove Oil Filter

1. Clean oil fi lter and housing area. Remove and
discard oil fi lter.

2. Remove dipstick and one of oil drain plugs.

3. Allow ample time for oil to drain from crankcase.

Remove Muffl er

Remove exhaust system and attaching hardware from
engine.

Remove Cylinder Shrouds and Blower Housing

1. Remove top mounting screw and loosen two
shoulder screws on each side. Lift off two cylinder
shrouds.

2. Remove four mounting screws and separate blower
housing from lower half.

3. Carefully pry off pal nut, remove two washers
(note assembly order), and disconnect choke linkage
from pivot lever. Do not lose any parts. Secure
remaining pivot parts with tape to avoid losing them.
Always use a new pal nut during reassembly.

4. Remove rear mounting screw on each side and lift
off control bracket.

5. Loosen hex fl ange nut and remove governor lever
from cross shaft.

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.

2. Remove fuel inlet hose from carburetor or fuel pump.
Properly contain any remaining fuel.

3. Remove carburetor and linkages with choke return
components as an assembly.

4. Remove carburetor gasket.

5. Carburetor and linkages can be separated as
necessary.

Remove Electric Starter Motor

1. Disconnect leads from starter.

2. Remove two hex fl ange screws and starter.

Remove Air Cleaner Assembly

NOTE: Low-profi le air cleaner is removed same way as

heavy-duty air cleaner.

1. Disconnect breather hose from air cleaner, and
formed vent hose from vent port on carburetor.

2. Remove four hex fl ange nuts, ground lead, and
choke return spring bracket from mounting studs.

3. Remove two screws securing air cleaner and main
control bracket to intake manifold bosses.

4. Remove air cleaner as an assembly from engine.

Removing Control Bracket, Governor Springs, and
Lever

1. Unhook governed idle and governor springs from
controls on main bracket and governor lever. Note
color, location and position of each.

2. Disconnect throttle linkage and dampening spring
from governor lever at small bushing.

Remove Oil Sentry™ (if equipped)

1. Disconnect lead from Oil Sentry™ switch.

2. Remove Oil Sentry™ switch from closure plate.

Remove Baffl es and Intake Manifold

1. Remove screws securing valley baffl es to cylinder
heads and backing shroud assembly.

2. Remove four screws securing each of outer cylinder
baffl es in place. Two of screws are accessed from
backing shroud side.

3. Remove four hex fl ange screws securing intake
manifold to cylinder heads. Cut any wire ties that
secure wiring harness or leads to intake manifold.

4. Remove intake manifold and gaskets.

Remove Oil Cooler

NOTE: New clamps are recommended any time

disassembly is performed, or if clamps have
been loosened (expanded) several times.

1. Remove two oil cooler mounting screws. Do not lose
any washers (if used).

2. Loosen clamps and disconnect each of hoses from
oil cooler.

48 62 690 01 Rev. CKohlerEngines.com

Disassembly

Remove Oil Filter Housing and Oil Filter Adapter

NOTE: Further disassembly of oil fi lter housing

assembly is not required unless individual
servicing must be performed. Follow substeps a,
b, and c.

1. Remove screw securing oil fi lter housing and
individual O-rings to adapter. Carefully separate
parts.

Perform following only if oil fi lter housing assembly

requires individual servicing.

a. Remove nipple from cup and oil fi lter housing.
b. Remove oil fi lter cup and spring from housing.
c. Remove rubber valve and spring from cup.

2. Remove screw securing oil fi lter adapter and
individual O-rings to crankcase, then carefully
separate parts.

Remove Ignition Modules

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

2. Remove mounting screws and disconnect kill lead
from ignition modules. Note position of ignition
modules.

Remove Grass Screen and Cooling Fan

Remove screws, attaching hardware and hex studs
securing grass screen, stiffeners and cooling fan to
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.

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

fl ywheel and loosen hex fl ange screw securing
fl ywheel to crankshaft.

2. Remove hex fl ange screw and washer.

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

4. Remove woodruff key from crankshaft.

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 gear as a serviceable part. Replace fl ywheel
if ring gear is damaged.

Remove Stator, Rectifi er-Regulator, and Wiring
Harness

1. Disconnect plug from rectifi er-regulator. If B+
(center) lead must be removed from plug, use a
small fl at tool to bend locking tang. Then remove
lead.

2. Remove mounting screws securing rectifi er-regulator
to backing shroud assembly. Note location of ground
lead. If rectifi er-regulator is not being replaced, it
may remain mounted to lower blower housing.

3. Remove two screws securing stator to crankcase
and carefully separate stator wires from blower
housing clips.

4. Unhook wiring harness from molded clips if it is
being serviced separately.

Remove Backing Shroud Assembly

Remove four mounting screws securing backing shroud
assembly to crankcase.

Remove Spark Plugs

Remove spark plug from each cylinder head.

Remove Valve Covers and 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.

NOTE: Based on style of fuel pump used refer to

following when removing valve covers.

Mechanical Fuel Pump

Mechanical fuel pump is part of valve cover and
not serviced separately. Remove with valve cover.
Disconnect fuel lines at fuel pump fi ttings. Properly
contain any remaining fuel.

Electric Fuel Pump

Removal will be determined based on mounted location
and application. Disconnect lead connections, fuel
line connections, and mounting hardware as required.
Properly contain any remaining fuel.

Valve Covers

1. Remove screw and grommet securing each valve
cover.

2. Remove valve cover and gasket from each cylinder
head. Note locations of individual valve covers if
they are different.

4962 690 01 Rev. C KohlerEngines.com

Disassembly

Remove Cylinder Heads and Hydraulic Lifters

NOTE: Exhaust lifters are located on output shaft side

of engine while intake lifters are located on fan
side of engine. Cylinder head number is
embossed on outside of each cylinder head.

1. Remove pipe plug from cylinder head to access
screw in upper center location.

2. Remove fi ve hex fl ange screws securing each
cylinder head. Note locations of washers and spacer.

3. Mark position of push rods as either intake or
exhaust and cylinder 1 or 2. Push rods should
always be reinstalled in same positions.

4. Carefully remove push rods, cylinder head and head
gasket.

5. Repeat procedure for or cylinder head.

6. 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.

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 two or three times to
force oil out of feed hole in side of lifter.

Disassemble Cylinder Heads

NOTE: These engines use valve stem seals on intake

and exhaust valves. Use a new seal whenever
valves are removed, or if seal is deteriorated in
any way. Never reuse an old seal.

1. Remove two hex fl ange screws, rocker arm pivots,
and rocker arms from cylinder head.

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 seals

Inspection and Service

After cleaning, check fl atness of cylinder head and
corresponding top surface of crankcase, using a surface
plate or piece of glass and feeler gauge. Maximum
allowable out of fl atness is 0.076 mm (0.003 in.).

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.

Then, carefully inspect each valve for defects such as a
warped head, excessive corrosion, or a 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
or exhaust clearance exceeds specifi cations, determine
whether valve stem or guide is responsible for excessive
clearance.

Maximum (I.D.) wear on intake valve guide is 7.135 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.

4. Repeat above procedure for or cylinder head. Do not
interchange parts from one cylinder head to or.

50 62 690 01 Rev. CKohlerEngines.com

Disassembly

Lapping Valves

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.

Valve Stem Seals

These engines use valve stem seals on intake and
exhaust valves. Always use new seals when valves
are removed from cylinder head. Seals should also be
replaced if deteriorated or damaged in any way. Never
reuse an old seal.

Remove Breather Assembly

1. Remove four fasteners securing breather assembly,

breather adapter (style based on spec), and gaskets
to crankcase.

2. Carefully break gasket seals and remove all parts.

Do not pry on sealing surfaces as it could cause
damage resulting in leaks. Note assembly and
orientation of parts.

Remove Oil Reservoir and Pickup Screen

1. Remove eight screws securing oil reservoir and

gasket to engine.

2. Remove mounting screw and carefully work pickup

screen off end of pickup tube.

Remove Closure Plate Assembly

1. Remove fourteen hex fl ange screws securing

closure plate to crankcase.

2. Locate two protruding tabs on closure plate.

Carefully tap to break gasket seal. Do not pry on
sealing surfaces as this could cause leaks. Separate
closure plate from crankcase. Remove old gasket.

Inspection

Inspect oil seal in closure plate and remove it if it is worn
or damaged.

Inspect main bearing surface for wear or damage.
Replace bearing or closure plate assembly if required.

Oil Pump Assembly

A

B

C

D

E

F

2

I

1

3

A Closure Plate B Gerotor Gears
C Oil Ring D Relief Valve
E Oil Pump F Inlet Seal
G Relief Valve Baffl e H Clamp

I Pickup Tube

Disassembly

1. Remove three hex fl ange screws securing oil pump
housing including relief valve baffl e, and single
screw with clamp for pickup tube.

2. Remove oil pump housing and pickup tube from
closure plate.

3. Remove oil pump gerotor gears from closure plate
recess.

4. Remove oil pickup by pulling it free from oil pump
body.

5. 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, gerotor gears, and closure
plate recess for nicks, burrs, wear, or any visible
damage. Inspect inlet seal for pickup tube in housing. If
any parts are worn or damaged, replace seal, oil pump
or closure plate as required.

G

H

5162 690 01 Rev. C KohlerEngines.com

Disassembly

Reassembly

1. Make sure recess in closure plate for oil pump
gerotor gears is clean.

2. Lubricate oil pump gerotor gears with grease
(Lubriplate® 100 or equivalent), and install into
recess.

3. Lightly lubricate with oil and install inlet seal into oil
pump housing until it is fully seated.

4. Install O-ring in groove of oil pump housing. Use a
small quantity of grease to hold it in place.

5. Lightly lubricate I.D. of inlet seal with oil and carefully
insert ferruled end of pickup tube through grommet,
into oil pump housing. Position pickup tube so
outboard end faces up.

6. Install oil pump housing with pickup tube, over oil
pump boss and gears. Position relief valve baffl e on
screws 2 and 3. Align three screw hole locations.

7. Install clamp for pickup tube and fi nger tighten
screw. Check alignment of parts and torque oil pump
housing screws as specifi ed using sequence below:

a. Install fastener into location No. 1 and lightly

tighten to position pump.

b. Install fastener into location No. 2 and fully torque

to recommended value.

c. Install fastener into location No. 3 and fully torque

to recommended value.

d. Finish torquing fastener in location No. 1 to

recommended value.

Tighten hex fl ange screws to torque specifi cations.

8. Torque clamp (pickup tube) mounting screw to
torque specifi cations.

Remove Camshaft

Remove camshaft and shim (if used).
Inspection and Service
Check lobes of camshaft for wear or damage. Inspect

cam gear for badly worn, chipped, or missing teeth.
Replacement of camshaft will be necessary if any of
these conditions exist.

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
ridge 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 two hex fl ange screws securing closest
connecting rod end cap. Remove end cap.

2. Carefully remove connecting rod and piston
assembly from cylinder bore.

3. Repeat above procedures for or connecting rod and
piston assembly.

Connecting Rods

Offset, stepped-cap connecting rods are used in these
engines.

Inspection and Service

Check bearing area (big end) for excessive wear, score
marks, running and side clearances. 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.
Always refer to appropriate parts information to ensure
that correct replacements are used.

Piston and Rings

A

B

C

D

E

F

G

I

H

A Piston Ring B End Gap
C

E

G Rails H Expander

I

Inspection

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 boss­piston 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.

Identifi cation

Mark

Top Compression

Ring

Oil Control Ring

(Three Piece)

D Piston

Center

F

Compression

Ring

52 62 690 01 Rev. CKohlerEngines.com

Disassembly

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 two 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
in 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 reuse old rings.

Some important points to remember when servicing
piston rings:

1. Cylinder bore must be deglazed before service ring

sets are used.

2. If cylinder bore does not need reboring 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 two

rings, each in turn, in its running area in cylinder
bore and check end gap. Compare ring gap to
specifi cations.

5. After installing new compression (top and middle)

rings on piston, match piston-to-ring side clearance
to specifi cations. If side clearance is greater than
specifi ed, a new piston must be used.

Install New Piston Rings

To install new piston rings, proceed as follows:
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.

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

Remove Crankshaft

High Point from Fillet
Intersections

Fillet Must Blend
Smoothly with
Bearing Journal
Surface

NOTE: If crankpin is reground, visually check to ensure

that fi llet blends smoothly with crankpin surface.

Carefully pull crankshaft from crankcase. Note thrust
washers and shims if used.

Inspection and Service

A Self-Tapping Screw B Flat Washer
C Plug D Crankshaft

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. Replaceable bearings are used in
crankshaft bore of closure plate and/or crankcase.
Do not replace bearings unless they show signs of
damage or are out of running clearance specifi cations.
If crankshaft turns easily, without noise, and there is no
evidence of scoring, grooving, etc., on races or bearing
surfaces, bearings can be reused.

45°

Minimum

This Fillet Area
Must Be
Completely Smooth

A

B

C

D

5362 690 01 Rev. C KohlerEngines.com

Disassembly

Inspect crankshaft keyways. If they are 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
and Tolerances 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 one size under.
When grinding a 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 that may collect in oil passages.

Use following procedure to remove and replace plug.
Procedure to Remove Crankshaft Plug:

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

2. Thread a 3/4 in. or 1 in. 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:

1. Use a 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 Governor Gear Assembly

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. If governor
cross shaft, yoke, or gear condition does not require
removal, governor gear may be left in place. If removal
is necessary, perform as follows:

1. Remove locking tab thrust washer and note
orientation.

2. Using a screwdriver, carefully pry upward to unseat
governor gear assembly from governor gear shaft.
Remove regulating pin and governor gear assembly.

3. Inspect governor gear shaft for wear or damage.
Remove shaft only if replacement is needed.

Inspection

Governor gear is located within crankcase. 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.

Remove Lifter Feed Chamber Cover and Gaskets

Remove three screws securing lifter feed chamber
baffl e (some models only), cover, and gaskets. Carefully
separate parts from crankcase.

Remove Flywheel and PTO End Oil Seals

Remove oil seals from crankcase and closure plate
using a seal puller.

Remove Main Bearings

NOTE: Flywheel and PTO side main bearings should

only be removed if replacement is required due
to wear. If removal is performed, use a press
and support casting surface around bearing
fl ange. Do not press against or support by
gasket/outer perimeter surface.

Crankcase
Inspection and Service

Check all gasket surfaces to make sure they are free of
gasket fragments. Gasket surfaces must also be free of
deep scratches or nicks.

Inspect main bearing (if so equipped) for wear or
damage. Replace bearing or crankcase using a
miniblock or short block as required.

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,
then select nearest suitable oversize of either 0.25 mm
(0.010 in.) or 0.50 mm (0.020 in.). Resizing to one of
these oversizes will allow usage of available oversize
piston and ring assemblies. Initially, resize using a boring
bar, then use following procedures for honing cylinder.

Remove Governor Yoke, Cross Shaft, and Seal

1. Remove two mounting screws securing yoke to
governor cross shaft.

2. Pull governor cross shaft out of crankcase and
remove seal.

54 62 690 01 Rev. CKohlerEngines.com

Honing Clean Cylinder Bore After Honing

23°-33°
Crosshatch

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 one 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 that is 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

Disassembly

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.
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.
Measurements should be taken at three locations in
cylinder – at top, middle, and bottom. Two
measurements should be taken
(perpendicular to each other) at each of three
locations.

11 mm (0.433 in.)

Measure 11 mm above
Bottom of Piston Skirt at
Right Angles to Piston Pin

Before installing piston into cylinder bore, it is necessary
that clearance be accurately checked. This step is
often overlooked, and if clearances are not within
specifi cations, engine failure will usually result.

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

bore clearance – it will yield inaccurate
measurements. Always use a micrometer.

Use following procedure to accurately measure piston­to-bore clearance:

1. Use a micrometer and measure diameter of piston
11 mm (0.433 in.) 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 difference between bore
diameter and piston diameter (step 2 minus Step 1).

5562 690 01 Rev. C KohlerEngines.com

Reassembly

General

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

®

is

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 closure plate, crankcase, cylinder heads, and
valve covers to be certain all old gasket 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 clean engine oil to outside
diameter of oil seal.

3. Install 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 Lifter Feed Chamber Gaskets and Cover

1. Install lifter feed chamber gasket, followed by lifter
feed cover over lifter feed chamber. If used, position
breather baffl e on top of parts with winged offset
down.

2. Install three screws. Make sure all parts are properly
aligned. Tighten screws to torque specifi cation.

Install Flywheel End Main Bearing

If fl ywheel end main bearing was removed in servicing,
install a new bearing using an arbor press and driver.

1. Make sure crankcase bore for main bearing is clean,
dry and free of nicks or burrs.

2. Press fl ywheel side main bearing in place with notch
oriented in 12 o’clock position using an arbor press
and driver. Make sure bearing is fully seated against
fl ange and oil feed hole is open in crankcase.

3. Apply a light coat of clean engine oil to inner surface
of main bearing.

Install Governor Shafts, Seal, and Governor Gear

Seal Depth

1.5-2.0 mm (0.059-0.078 in.)

Crankcase
Surface

Oil Seal

12.66 mm
(0.498 in.)

Governor
Gear Shaft

Crankcase
Surface

If governor shafts, seal, and/or governor gear were
removed, reassemble as follows.

1. Lightly oil lip and outside diameter of new governor
cross shaft seal. Install seal into crankcase to depth
shown.

2. If governor gear shaft was removed, press or lightly
tap replacement shaft into closure plate to depth
shown.

3. Lubricate governor cross shaft bearing surfaces in
crankcase with engine oil. Insert end with fl at for
governor gear yoke into crankcase fi rst and position
so fl at is up.

4. Attach governor yoke to cross shaft so curved
section is up as marked. Secure with two screws. If
a thread locking compound is not preapplied, apply a
small amount of Loctite® 266™ Threadlocker or
equivalent, to screw threads before installing.
Tighten screws to torque specifi cation.

5. Install fi rst regulating pin with head down so it will
contact yoke. Install governor gear with second
regulating pin and fl yweight assembly in/down onto
governor shaft until it locks into position. Apply a
small amount of grease to locking tab thrust washer
and install on top of governor gear so tang is facing
up in 6 o’clock position.

56

Install Crankshaft

Carefully slide fl ywheel end of crankshaft through main
bearing in crankcase.

KohlerEngines.com 62 690 01 Rev. C

Reassembly

Install Connecting Rods with Pistons and Rings

Top of Piston

No. 1
Side

NOTE: Cylinders are numbered on crankcase. Make

sure to install piston, connecting rod and end
cap into 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.

1. Stagger piston rings in grooves until end gaps are
120° apart. Oil ring rails should also be staggered.

2. Lubricate cylinder bore, piston, and piston rings with
engine oil. Compress rings of #1 piston using a
piston ring compressor.

3. Lubricate crankshaft journals and connecting rod
bearing surfaces with engine oil.

4. Make sure FLY stamping on piston is facing toward
fl ywheel side of engine. Use a hammer with a rubber
grip and gently tap piston into cylinder. Be careful 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 two hex
fl ange screws. Tighten screws in increments to
torque specifi cations. Illustrated instructions are
provided in service rod package.

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.

6. Repeat this procedure for other connecting rod and
piston assembly.

No. 2
Side

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. 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. Place a new closure plate gasket into position on
crankcase.

2. Position camshaft end play checking tool over
camshaft. Use a feeler gauge to check end play
between camshaft and end play checking tool.
Camshaft endplay should match specifi cations.

3. No shim is typically used from factory. However, if
camshaft end play is not within specifi ed range,
remove checking tool and 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.)

4. Reinstall end play checking tool and recheck end
play.

Install Closure Plate Main Bearing and Oil Seal
Main Bearing

If closure plate main bearing was removed during
servicing, install a new bearing.

1. Make sure closure plate bore for main bearing is
clean, dry, and free of nicks or burrs.

2. Install a new bearing with notch in 12 o’clock
position, using a press and driver. Make sure
bearing is fully seated against fl ange.

3. Lightly oil inside diameter of bearing.

62 690 01 Rev. C KohlerEngines.com

57

Reassembly

Oil Seal

3.0 mm
(0.118 in.)

Oil Seal

1. Check to make sure there are no nicks or burrs in
crankshaft seal bore of closure plate.

2. Lightly oil outside diameter of oil seal.

3. Install oil seal into closure plate using a seal driver.
Make sure oil seal is installed straight and true in
bore to depth shown.

4. Apply a light coat of clean engine oil to inner surface
of main bearing.

Oil Pump Assembly

Oil pump is mounted inside closure plate. If service was
required and oil pump was removed, refer to assembly
procedure.

5. Orient fl at of oil pump gear to match position of fl at
on camshaft. Then install closure plate to crankcase.
Carefully seat camshaft and crankshaft into their
mating bearings. Rotate crankshaft slightly to help oil
pump and governor gears mesh.

6. Install hex fl ange screws securing closure plate to
crankcase. Tighten screws in sequence shown to
torque specifi cation.

Install Oil Pickup Screen

Apply a small amount of oil to grommet of pickup
screen and insert it onto lower end of pickup tube
within crankcase. Secure pickup to boss on bottom
of crankcase. Tighten mounting screw to torque
specifi cation.

Install Oil Reservoir

8

5

1

2

6

43

7

Install Closure Plate Assembly

3

5

7

9

11

13

1. Make sure sealing surfaces of closure plate and
crankcase are clean, dry, and free of any nicks or
burrs. Install a new O-ring in closure plate.

2. Install a new closure plate gasket onto crankcase.

3. Make sure oil pump is installed and oil pickup tube
faces outward at lower end.

4. Ensure end of tabbed washer on governor gear is
positioned outward in 6 o’clock position inside
crankcase.

1

14

12

10

8

6

2

4

1. Use two bolts with heads removed, or a similar item
as temporary alignment pins and install into two
center holes on ends.

2. Install a new oil reservoir gasket onto bottom of
crankcase using alignment pins. Notched side of
gasket must be towards fl ywheel.

3. Install oil reservoir onto crankcase and temporary
alignment pins. Flywheel side is indicated on cover.
Install and fi nger tighten screws. Remove two
alignment pins and install two remaining screws.
Tighten screws in sequence shown to torque
specifi cation.

Check Crankshaft End Play

Set engine on base, and use a dial indicator to check
crankshaft end play against specifi cation.

58

KohlerEngines.com 62 690 01 Rev. C

Reassembly

Used on Serial No. 37070xxxxx and Below Used on Serial No. 37071xxxxx and Higher

Breather Fastener

A

Torque Sequence

1

3

A

B

C

D

E

H

D

I

A Breather Hose B Flange Nuts C Breather D Gasket
E Screw F Baffl e G Filter H Adapter

I Studs

Install Breather Assembly

1. Make sure sealing surfaces of crankcase and
breather cover are clean and free of any nicks or
burrs. Do not scrape surfaces, as this could result in
leakage. Install four breather mounting studs into
crankcase if removed during disassembly.

2. Install breather chamber gasket as shown. Assemble
and install breather assembly components as
illustrated. Make sure fi lter does not extend above
top surface and all parts are properly aligned.

3. Install M5 hex fl ange nuts onto studs, then tighten
using sequence shown to torque specifi cation.

4. Lightly oil lower end of breather hose and install into
hole in breather assembly. Cover should be situated
between two raised rings of hose.

F

G

A

4

Filter Mist Not Extend
Above Casting

A

2

SECTION A-A

Install Hydraulic Lifters

NOTE: Hydraulic lifters should always be installed in

same position as they were disassembled.
Exhaust lifters are located on output shaft 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. See Servicing Hydraulic Lifters in disassembly for
lifter preparation (bleed down) 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 location in
crankcase. Do not use a magnet.

I

B

C

D

H

D

G

62 690 01 Rev. C KohlerEngines.com

59

Reassembly

Valve Stem Seals

These engines use valve stem seals on intake and
exhaust valves. Always use new seals whenever valves
are removed from cylinder head. Seals should also be
replaced if worn or damaged. Never reuse an old seal.

Assemble Cylinder Heads

E

F

BA

A Exhaust Valve B Intake Valve
C Spring D Retainer
E Keepers F Valve Stem Seals

Prior to installation, lubricate all components with engine
oil, paying particular attention to lip of valve stem seal,
valve stems, and valve guides. Install following items in
order listed below using a valve spring compressor.

● Intake and exhaust valves

● Valve spring retainers

● Valve springs

● Valve spring keepers

● Valve stem seals

Install Cylinder Heads

2

4

3

1

No. 1

NOTE: Match numbers embossed on cylinder heads

and crankcase.

1. Check to make sure there are no nicks or burrs on
sealing surfaces of cylinder head or crankcase.

2. Check dowel pins are in place in two lower locations,
and install a new cylinder head gasket,
(printed side up).

3. Install cylinder head. Make sure head is fl at on
gasket and dowel pins. Install a fl at washer on
screws in locations 1 and 3. Install spacer followed
by a fl at washer on screw in location 5. See Figures
10-48 and 10-50. Start fi ve hex fl ange screws.

5

5

No. 2

D

C

2

4

13

4. Tighten hex fl ange screws in two stages following
sequence shown to torque specifi cation.

5. Repeat procedure for opposite cylinder.

6. Make sure threads of pipe plugs for cylinder heads
are clean and dry. Install a plug into each cylinder
head above No. 2 screw location and tighten to
torque specifi cation.

Install Push Rods and Rocker Arms

NOTE: Push rods should always be installed in same

position as before disassembly.

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 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 No. 1 cylinder head, and start two hex
fl ange screws.

3. Rotate crankshaft to establish Top Dead Center
(TDC) on compression stroke. Keyway should be
aligned with No. 1 cylinder.

4. Tighten screws to torque specifi cation.

5. If push rods were not already seated, use a spanner
wrench or rocker arm lifting tool, to lift rocker arms
and position push rods underneath.

6. From PTO end, rotate crankshaft 270° (3/4 turn)
counterclockwise and align crankshaft keyway with
No. 2 cylinder. This now puts No. 2 cylinder at TDC
on compression stroke.

7. Repeat Steps 1-5 for remaining cylinder. Do not
interchange parts from cylinder heads.

8. Rotate crankshaft to check for free operation of
valve train. Check clearance between valve spring
coils at full lift. Minimum allowable clearance is
specifi ed in specifi cations.

Install Valve Covers

1. Make sure sealing surfaces are clean and free of
any nicks or burrs.

2. Install and properly seat seal onto each valve cover.

3. Install valve covers on same side as they were
originally installed.

4. Install a new grommet on each valve cover mounting
screw. Start each screw into hole.

5. Check position of each cover and seal, then tighten
screws to torque specifi cation.

6. Install oil fi ll cap onto valve cover (if equipped).

Install Spark Plugs

1. Use new Kohler spark plugs.

2. Set gap to specifi cations.

3. Install new plugs and tighten to torque specifi cation.

60

KohlerEngines.com 62 690 01 Rev. C

Reassembly

Install Oil Filter Adapter

K

J

M

N

M

L

K

I

J

A Oil Filter B Oil Filter Nipple
C Cup D Valve Spring
E Cup Spring F Oil Filter Valve
G Oil Filter Housing H Pin

I O-ring J Hose Clamp

K Fitting L Adapter

M Hose N Oil Cooler

1. Make sure all sealing surfaces are clean and three
dowel pins are in place on crankcase adapter
surface. Carefully install a new O-ring around each
dowel pin. Then install three new O-rings onto dowel
pins of oil fi lter adapter.

2. Install oil fi lter adapter onto crankcase. Install and
tighten M8 capscrew to torque specifi cation.

Install Intake Manifold

3

1. Install new intake manifold gaskets so notched
section is inward and points toward fl ywheel side.

2. Mount intake manifold to cylinder heads. Make sure
gaskets remain in proper position. Tighten four
screws in two stages using sequence shown to
torque specifi cation.

3. Install carburetor mounting studs into intake manifold
if previously removed. Use two hex nuts, locked
fl ange to fl ange, and tighten each stud until
bottomed/tight.

I

1

H

2

A

B

C

D

E

F

G

4

Install Oil Filter Housing Assembly

Reassemble oil fi lter housing if disassembled previously.

Reassembly

1. Install small spring onto rubber valve, and insert
small end through corresponding hole in cup until
properly seated.

2. Install larger spring into fi lter housing.

3. Insert oil fi lter cup, aligning cutout with
corresponding section in housing.

4. Install nipple in housing and tighten to torque
specifi cation.

Installation

1. Make sure all sealing surfaces are clean and all
three dowel pins are in position. Install or check new
O-rings are around all three oil fi lter adapter dowel
pins.

2. Install oil fi lter housing assembly to adapter and
secure with M8 hex head screw. Make sure housing
is fl at on crankcase and all O-rings remain in
position. Tighten screw to torque specifi cation.

3. Oil fi lter may be installed now or upon completion of
engine assembly.

Install Backing Shroud Assembly

NOTE: New hose clamps are recommended for

reassembly, or if clamps have been loosened
(expanded) several times to avoid leakage.

1. To aid assembly, install lower oil cooler hose onto oil
fi lter housing prior to installing backing shroud
assembly, and secure with a clamp.

2. Install backing shroud assembly and secure to
crankcase with four M6 screws. Tighten screws to
torque specifi cation.

Install Stator, Wiring Harness, and Rectifi er-
Regulator

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 leads are
at bottom and toward rectifi er-regulator mount on
No. 1 side.

3. Install and tighten hex fl ange screws to torque
specifi cation.

4. Route stator wires under two molded clips in backing
shroud assembly.

5. Check terminal on end of B+ charging lead to be
sure locking tang is angled upward. Insert terminal
into center location of connector until it locks into
place.

6. Install wiring harness under molded clips in backing
shroud assembly.

7. Position rectifi er-regulator onto mounting posts with
cooling fi ns up. Attach ground lead to outer screw
and washer, then tighten mounting screws to torque
specifi cation. Connect plug to rectifi er-regulator.

62 690 01 Rev. C KohlerEngines.com

61

Reassembly

Install Flywheel

WARNING: Damaging Crankshaft and Flywheel Can

Cause Personal Injury!

Using improper procedures to install fl ywheel can
crack or damage crankshaft and/or fl ywheel. This not
only causes extensive engine damage, but can also
cause personal injury, since broken fragments could be
thrown from engine. Always observe and use following
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 hex fl ange 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 crankshaft keyway. 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 hex fl ange screw and washer.

4. Use a fl ywheel strap wrench or holding tool to hold
fl ywheel. Tighten hex fl ange screw to torque
specifi cation.

Install Ignition Modules

1. Rotate fl ywheel to position magnet away from
ignition module bosses.

2. Connect ground lead to single kill tab and install
modules onto crankcase bosses so tab is away from
you (in). Spark plug lead should be towards you
(out). Mount wiring harness clamp with loop up, on
starter (No. 1) side inner module screw and route
harness through it. Attach rectifi er-regulator ground
lead to outer screw.

3. Slide modules up as far away from fl ywheel as
possible and snug screws to hold them in 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 down
against feeler gauge.

6. Tighten screws to torque specifi cation.

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.).

9. Make sure leads are under molded clip on starter
side.

Install Outer Cylinder Baffl es

1. Install outer cylinder baffl es. Make sure spark plug
lead is routed through corresponding opening in
each baffl e. Start each screw. Tighten M6 shoulder
screws going through backing shroud assembly into
extruded holes in baffl es to torque specifi cations.

Tighten M6 screws going into cylinder head and

crankcase to torque specifi cations.

Install Oil Cooler

1. Connect two hoses between oil fi lter adapter and oil
cooler. Secure with new clamps.

2. Align oil cooler with bosses in backing shroud
assembly. Secure with two screws and washers.

Install Cooling Fan and Grass Screen

A

B

F

A Special Washers B Stiffener
C Fan Screws D Fan
E Mounting Studs F Grass Screen

Failure to utilize or reassemble grass screen as
designed could result in grass screen failure and serious
personal injury.

1. Position cooling fan onto fl ywheel aligning mounting
locations. Apply a small amount of Loctite® 243™
Threadlocker to threads and install three long
mounting screws. Tighten screws to torque
specifi cation.

2. Apply a small amount of Loctite® 243™ Threadlocker
to external threaded section, (unless new parts with
preapplied locking compound are being used).
Thread four grass screen hex studs into mounting
holes in fl ywheel. Tighten each stud to torque
specifi cation.

3. Install stiffener followed by metal grass screen onto
four hex studs. Secure with four special washers and
mounting screws using Loctite® 243™ Threadlocker
on threads. Tighten screws to torque specifi cation.

Install Electric Starter

1. Install electric starter motor using two hex fl ange
screws.

2. Tighten hex fl ange screws to torque specifi cation.

3. Connect leads to solenoid.

E

CAUTION

C

D

62

KohlerEngines.com 62 690 01 Rev. C

Reassembly

Install Valley Baffl es

Install two valley baffl es and secure with mounting
screws. Lower section should fi t under outer baffl e.
Tighten M6 screws going into cylinder head to torque
specifi cation. Start upper M6 screws only if main control
bracket rear supports attach to these screws.

Tighten M6 screw going into lower blower housing
mounting clip to torque specifi cation.

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 onto intake manifold
with tab up. Make sure all holes align and are open.

2. Attach choke return spring and bracket to front hole
in choke lever on carburetor.

3. Connect throttle and choke linkages to carburetor if
they were previously disconnected. Install carburetor
with linkages attached as an assembly.

4. Connect fuel line to carburetor inlet and secure with
a clamp.

Install Governor Lever

Install governor lever onto governor shaft and connect
throttle linkage with black clip. Do not tighten governor
lever at this time.

Install Control Bracket and Air Cleaner Assembly

3

2

NOTE: Low-profi le air cleaner is installed similarly to

Heavy-duty air cleaner.

1, 5

4

1. Position control bracket assembly onto two intake
manifold bosses. Align rear supports with top valley
baffl e/cylinder head mounting screw locations and
install two screws, but do not fully tighten.

2. Connect choke link to control pivot pin. Reinstall
washer and secure with a new push-on pal nut.

3. Install a new air cleaner elbow gasket onto
carburetor mounting studs.

4. Slide air cleaner assembly onto four carburetor
mounting studs. Align two forward mounting holes in
base with mounting holes/bosses of intake manifold
and control bracket. Attach ground lead under hex
nut as originally installed. Install remaining three hex
nuts and start two hex fl ange screws. Install rear
mounting screws into valley baffl e/cylinder head.
Check positions of all parts then tighten four hex
fl ange nuts to torque specifi cation in sequence
shown, and four hex fl ange screws to torque
specifi cation.

5. Connect breather hose to fi tting on air cleaner outlet
and connect fuel solenoid lead.

6. Connect formed vent hose to air cleaner housing
and vent port on carburetor.

Install Throttle and Choke Linkages

If individual throttle/choke lever control linkages were
disconnected during disassembly, reconnect them based
on operating direction of control cables to be used.

On Control Levers:

Hole A is used for Outer Pull control cable actuation.
Hole B is used for Inner Pull control cable actuation.

1. Connect choke linkage to appropriate hole in choke
lever and secure with small clip.

2. Connect throttle linkage to appropriate hole in
throttle lever and secure with small clip.

Adjusting Governor

1. Position governor lever so clamping area is inboard
but completely on knurled area of governor cross
shaft.

2. Move governor lever toward carburetor as far as it
will go (wide-open throttle) and hold in position.

3. Insert a long thin rod or tool into hole on cross shaft
and rotate shaft clockwise (viewed from end) as far
as it will turn, then tighten to torque specifi cation.

4. Ensure correct color springs are used. Connect
governor spring (with long looped end), to inner hole
on governor lever and control bracket.

Connect governed idle spring to outer governor lever

hole and control bracket. Long end of each spring
must be toward governor lever. Make sure springs
do not contact valley baffl e.

62 690 01 Rev. C KohlerEngines.com

63

Reassembly

Governor Spring/RPM Chart
CH940-CH1000

Governor Idle Spring Color) High Speed (RPM)

Clear 1400-1625 RPM

Black 1626-1800 RPM

CH940, CH960, CH980

Governor Spring (Color) High Speed (RPM)

Red 3000-3150 RPM

Green 3151-3300 RPM

Green Patch 3301-3675 RPM

Red Patch 3676-3900 RPM

CH1000

Governor Spring (Color) High Speed (RPM)

Yellow Patch 3000-3150 RPM

Purple Patch 3151-3450 RPM

Purple 3451-3900 RPM

Install Oil Sentry™ (if equipped)

1. Apply pipe sealant with Tefl on® (Loctite® PST® 592™
Thread Sealant or equivalent) to Oil Sentry™ threads
switch and install it into 1/8 in. port in closure plate.
Tighten switch to torque specifi cation.

2. Connect green wire lead to Oil Sentry™ terminal.

Install Blower Housing and Cylinder Shrouds

1. Align and install blower housing.

2. Secure blower housing with four shoulder screws.
Tighten screws to torque specifi cation.

3. Install two cylinder shrouds and secure with shoulder
screws. Tighten screws to torque specifi cation.

Install Control Panel (If Equipped)

1. Install control panel to main control bracket and oil
fi lter housing. Tighten M5 and M6 screws to torque
specifi cation.

2. Connect Oil Sentry™ indicator light wires.

3. Install knobs onto control levers.

Install Oil Filter and Add Oil to Crankcase

NOTE: Make sure both oil drain plugs are installed and

tightened to torque specifi cations to prevent oil
leakage.

1. Install oil drain plugs. Tighten plugs to torque
specifi cation.

2. Install new oil fi lter.

3. Apply a thin fi lm of clean engine oil to rubber gasket
on oil fi lter and thread fi lter onto adapter nipple.

4. Install new oil fi lter to fi lter adapter or oil cooler.

5. Add oil to bring level up to F mark. Reinstall dipstick
and oil fi ll cap.

Connect Spark Plug Leads

Connect leads to spark plugs.

Prepare Engine for Operation

Engine is now completely reassembled. Before starting
or operating engine, follow proceeding steps.

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. Fill crankcase with correct amount, weight, and type
of oil.

4. Adjust carburetor, idle fuel needles, or idle speed
adjusting screw as necessary.

Testing Engine

It is recommended engine be operated on a test stand or
bench prior to installation in equipment.

1. Set engine up on a test stand. Install an oil pressure
gauge. Start engine and check to be certain 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 governed idle and high speed (RPM) to
required settings. Make sure maximum engine
speed does not exceed 3900 RPM (no load).

Install Muffl er

1. Install new exhaust gaskets onto exhaust studs.

2. Install port liners (if equipped). Attach muffl er and
secure with four hex fl ange nuts onto exhaust studs.
Tighten hex fl ange screws to torque specifi cation.

3. Install any attaching hardware and brackets. Tighten
M6 and M8 screws to torque specifi cation.

4. Install spark arrestor (if used).

64

KohlerEngines.com 62 690 01 Rev. C

FOR SALES AND SERVICE INFORMATION
IN U.S. AND CANADA, CALL 1-800-544-2444

KohlerEngines.com
ENGINE DIVISION, KOHLER CO., KOHLER, WISCONSIN 53044
© 2011 by Kohler Co. All rights reserved.

FORM NO.: 62 690 01 Rev. C
ISSUED: 9/10
REVISED: 5/11