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.
2Safety
3Maintenance
5Specifi cations
13Tools and Aids
16Troubleshooting
20Air Cleaner/Intake
21Fuel System
27Governor System
28Lubrication System
30Electrical System
38Starter System
42Disassembly/Inspection and Service
56Reassembly
62 690 02 Rev. D1
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.
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.
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.
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.
WARNING
WARNING
WARNING
Electrical Shock can
cause injury.
Do not touch wires while
engine is running.
Damaging Crankshaft
and Flywheel can cause
personal injury.
Using improper procedures can
lead to broken fragments. Broken
fragments could be thrown from
engine. Always observe and use
precautions and procedures when
installing fl ywheel.
Failure to utilize or
reassemble debris
screen as designed could
result in debris screen
failure and serious
personal injury.
CAUTION
CAUTION
CAUTION
262 690 02 Rev. DKohlerEngines.com
Maintenance
MAINTENANCE INSTRUCTIONS
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
Every 150 Hours
● Check heavy-duty air cleaner element.Air Cleaner/Intake
● Replace fuel fi lter.
● Check oil cooler fi ns, clean as necessary.Lubrication System
Before working on engine or equipment, disable engine as
follows: 1) Disconnect spark plug lead(s). 2) Disconnect
negative (–) battery cable from battery.
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
Kohler genuine service parts can be purchased from Kohler authorized dealers. To fi nd a local Kohler authorized
dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada).
362 690 02 Rev. DKohlerEngines.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 02 Rev. DKohlerEngines.com
Engine Dimensions
Specifi cations
Dimensions in millimeters.
Inch equivalents shown in [ ].
(Optional Guard)
KohlerEngines.com
562 690 02 Rev. D
Specifi cations
ENGINE IDENTIFICATION NUMBERS
Kohler engine identifi cation numbers (model, specifi cation and serial) should be referenced for effi cient repair,
ordering correct parts, and engine replacement.
Year Manufactured Code Factory Code
Code Year
39 2009
40 2010
41 2011
GENERAL SPECIFICATIONS
3,6
CV940CV960CV980CV1000
Bore90 mm (3.54 in.)
Stroke78.5 mm (3.1 in.)
Displacement999 cc (61 cu. in.)
Oil Capacity (refi ll)2.9 L (3.1 U.S. qt.)
Maximum Angle of Operation (@ full oil level)
Intake Manifold Mounting Fastener (torque in 2 increments)fi rst to 16.9 N·m (150 in. lb.)
fi nally to 22.6 N·m (200 in. lb.)
Carburetor/Air Cleaner Mounting Nut7.9 N·m (70 in. lb.)
Air Cleaner Mounting Screw (into intake manifold)9.9 N·m (88 in. lb.)
Fuel Bowl Screw2.5 ± 0.3 N·m (22 ± 2.3 in. lb.)
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 Fastener5.7 N·m (51 in. lb.)
Oil Drain Plug21.4 N·m (16 ft. lb.)
Dipstick Tube Screw4.0 N·m (35 in. lb.)
3
Values are in Metric units. Values in parentheses are English equivalents.
4
Exceeding maximum angle of operation may cause engine damage from insuffi cient lubrication.
5
Lubricate threads with engine oil prior to assembly.
6
Any and all horsepower (hp) references by Kohler are Certifi ed Power Ratings and per SAE J1940 & J1995 hp
standards. Details on Certifi ed Power Ratings can be found at KohlerEngines.com.
6
62 690 02 Rev. DKohlerEngines.com
Specifi cations
TORQUE SPECIFICATIONS
3,5
CV940CV960CV980CV1000
Cylinder Head
Fastener (torque in 2 increments)
Head Boltfi 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 Stud (AVT) 11.3 N·m (100 in. lb.)
Setscrew, AVT pivot locking7.3 N·m (65 in. lb.)
Debris Screen
Hex Stud9.9 N·m (88 in. lb.)
Mounting Screw9.9 N·m (88 in. lb.)
Flywheel
Fan Fastener9.9 N·m (88 in. lb.)
Retaining Screw67.8 N·m (50 ft. lb.)
Fuel Pump
Screw8.0-12.1 N·m (71-107 in. lb.) into new holes
6.0-9.0 N·m (53-80 in. lb.) into used holes
Governor
Lever Nut7.3 N·m (65 in. lb.)
Yoke Mounting Screw2.2 N·m (20 in. lb.)
Ignition
Spark Plug27 N·m (20 ft. lb.)
Module Fastener6.2 N·m (55 in. lb.) into new holes
4.0 N·m (35 in. lb.) into used holes
Rectifi er-Regulator Fastener2.0 N·m (18 in. lb.)
Lifter Feed Chamber Cover
Screw6.2 N·m (55 in. lb.) into new holes
4.0 N·m (35 in. lb.) into used holes
Muffl er
Retaining Nut24.4 N·m (216 in. lb.)
Screw, intermittent bracket (into weld nut)13.5 N·m (120 in. lb.)
Oil Cooler
Mounting Screw2.2 N·m (20 in. lb.)
Oil Filter Adapter/Housing
Mounting Screw24.4 N·m (216 in. lb.)
Oil Filter Nipple18 N·m (159 in. lb.)
Oil Pan
Fastener27 N·m (238 in. lb.)
Oil Pickup Tube
Mounting Screw10.7 N·m (95 in. lb.) into a new hole
7.3 N·m(65 in. lb.) into a used hole
3
Values are in Metric units. Values in parentheses are English equivalents.
5
Lubricate threads with engine oil prior to assembly.
KohlerEngines.com
762 690 02 Rev. D
Specifi cations
TORQUE SPECIFICATIONS
3,5
CV940CV960CV980CV1000
Oil Pump
Mounting Screw10.7 N·m (95 in. lb.) into new holes
6.7 N·m (60 in. lb.) into used holes
Oil Sentry
TM
Pressure Switch10.1 N·m (90 in. lb.)
Solenoid (starter)
Mounting Hardware4.0-6.0 N·m (35-53 in. lb.)
Nut, Positive (+) Brush Lead8.0-11.0 N·m (71-97 in. lb.)
Starter Assembly
Thru Bolt5.6-9.0 N·m (49-79 in. lb.)
Mounting Screw15.3 N·m (135 in. lb.)
Brush Holder Mounting Screw2.5-3.3 N·m (22-29 in. lb.)
Stator
Mounting Screw6.2 N·m (55 in. lb.)
Throttle/Choke Control Bracket
Fastener9.9 N·m (88 in. lb.)
Valve Cover
Fastener13.6 N·m (120 in. lb.)
CLEARANCE SPECIFICATIONS
3
CV940CV960CV980CV1000
Camshaft
End Play0.3/1.3 mm (0.011/0.051 in.)
Running Clearance0.025/0.063 mm (0.0010/0.0025 in.)
Bore I.D.
New
Max. Wear Limit
20.000/20.025 mm (0.7874/0.7884 in.)
20.038 mm (0.7889 in.)
Bearing Surface O.D.
New
Max. Wear Limit
19.962/19.975 mm (0.7859/0.7864 in.)
19.959 mm (0.7858 in.)
Cam Lobe Profi le (minimum dimension, measured from base circle
to top of lobe)
Exhaust35 mm (1.3779 in.)
Intake34.1 mm
35 mm (1.3779 in.)
(1.3425 in.)
3
Values are in Metric units. Values in parentheses are English equivalents.
5
Lubricate threads with engine oil prior to assembly.
8
62 690 02 Rev. DKohlerEngines.com
Specifi cations
CLEARANCE SPECIFICATIONS
3
CV940CV960CV980CV1000
Connecting Rod
Crankpin End I.D. @ 70°F
New
Max. Wear Limit
44.030/44.037 mm (1.7334/1.7337 in.)
0.070 mm (0.0028 in.)
Connecting Rod-to-Crankpin Running Clearance
New
Max. Wear Limit
0.030/0.055 mm (0.0012/0.0022 in.)
0.070 mm (0.0028 in.)
Connecting Rod-to-Crankpin Side Clearance0.30/0.59 mm (0.0118/0.0232 in.)
Connecting Rod-to-Piston Pin Running Clearance0.015/0.028 mm (0.0006/0.0011 in.)
Piston Pin End I.D. @ 70°F
New
Max. Wear Limit
19.015/19.023 mm (0.7486/0.7489 in.)
19.036 mm (0.7494 in.)
Crankcase
Governor Cross Shaft Bore I.D.
New
Max. Wear Limit
8.025/8.050 mm (0.3159/0.3169 in.)
8.088 mm (0.3184 in.)
Crankshaft
End Play (free)0.30/1.50 mm (0.011/0.059 in.)
Bore (in crankcase)
New, Without Main Bearing
With Main Bearing Installed
Max. Wear Limit
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 to Sleeve Bearing (crankcase) Running Clearance
New0.040/0.167 mm (0.0015/0.0065 in.)
Bore (in oil pan)
New, Without Bearing50.025/50.00 mm (1.9694/1.9685 in.)
Crankshaft to Sleeve Bearing (in oil pan) Running Clearance
New0.040/0.167 mm (0.0015/0.0065 in.)
Oil Pan End Main Bearing Journal
O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round
Spark Plug Gap0.76 mm (0.030 in.)
Module Air Gap0.28/0.33 mm (0.011/0.013 in.)
Piston, Piston Rings, and Piston Pin
Piston-to-Piston Pin Running Clearance0.006/0.018 mm (0.0002/0.0007 in.)
Pin Bore I.D.
New
Max. Wear Limit
19.006/17.013 mm (0.7482/0.7485 in.)
19.025 mm (0.7490 in.)
Pin O.D.
New
Max. Wear Limit
18.995/19.000 mm (0.7478/0.7480 in.)
18.994 mm (0.7478 in.)
Top Compression Ring-to-Groove Side Clearance0.04/0.08 mm (0.0015/0.0031 in.)
Middle Compression Ring-to-Groove Side Clearance0.04/0.08 mm (0.0015/0.0031 in.)
Oil Control Ring-to-Groove Side Clearance0.03/0.19 mm (0.0011/0.0074 in.)
Top and Center Compression Ring End Gap
New Bore
Used Bore (max.)
Thrust Face O.D.
7
New
Max. Wear Limit
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.)
Piston Thrust Face-to-Cylinder Bore7 Running Clearance
New0.033/0.071 mm (0.0013/0.0028 in.)
3
Values are in Metric units. Values in parentheses are English equivalents.
7
Measure 11 mm (0.433 in.) above bottom of piston skirt at right angles to piston pin.
10
62 690 02 Rev. DKohlerEngines.com
Specifi cations
CLEARANCE SPECIFICATIONS
3
CV940CV960CV980CV1000
Valves and Valve Lifters
Hydraulic Valve Lifter to Crankcase Running Clearance0.012/0.050 mm (0.0004/0.0019 in.)
Intake Valve Stem-to-Valve Guide Running Clearance0.038/0.076 mm (0.0015/0.0030 in.)
Exhaust Valve Stem-to-Valve Guide Running Clearance0.050/0.088 mm (0.0020/0.0035 in.)
Intake Valve Guide I.D.
New
Max. Wear Limit
7.038/7.058 mm (0.2771/0.2779 in.)
7.135 mm (0.2809 in.)
Exhaust Valve Guide I.D.
New
Max. Wear Limit
7.038/7.058 mm (0.2771/0.2779 in.)
7.159 mm (0.2819 in.)
Guide Reamer Size
Standard
0.25 mm O.S.
7.048 mm (0.2775 in.)
7.298 mm (0.2873 in.)
Nominal Valve Face Angle45°
3
Values are in Metric units. Values in parentheses are English equivalents.
KohlerEngines.com
1162 690 02 Rev. D
Specifi cations
GENERAL TORQUE VALUES
English Fastener Torque Recommendations for Standard Applications
Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel
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
DescriptionSource/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
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 810-664-2981
Toll Free 800-664-2981
Fax 810-664-8181
Design Technology Inc.
768 Burr Oak Drive
Westmont, IL 60559
Phone 630-920-1300
Fax 630-920-0011
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 LubricantKohler 25 357 12-S
1462 690 02 Rev. DKohlerEngines.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 TOOLROCKER ARM/CRANKSHAFT TOOL
A fl ywheel holding tool can be made out of an old junk
fl ywheel ring gear and used in place of a strap wrench.
1. Using an abrasive cut-off wheel, cut out a six tooth
segment of ring gear as shown.
2. Grind off any burrs or sharp edges.
3. Invert segment and place it between ignition bosses
on crankcase so tool teeth engage fl ywheel ring
gear teeth. Bosses will lock tool and fl ywheel in
position for loosening, tightening, or removing with a
puller.
A spanner wrench to lift rocker arms or turn crankshaft
may be made out of an old junk connecting rod.
1. Find a used connecting rod from a 10 HP or larger
engine. Remove and discard rod cap.
2. Remove studs of a Posi-Lock rod or grind off
aligning steps of a Command rod, so joint surface is
fl at.
3. Find a 1 in. long capscrew with correct thread size to
match threads in connecting rod.
4. Use a fl at washer with correct I.D. to slip on
capscrew and approximately 1 in. O.D. Assemble
capscrew and washer to joint surface of rod.
1562 690 02 Rev. DKohlerEngines.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 plug(s).
● Fuel pump malfunction-vacuum hose clogged or
leaking.
● Fuel shut-off valve closed.
● Ignition module(s) faulty or improperly gapped.
● Insuffi cient voltage to electronic control unit.
● Interlock switch is engaged or faulty.
● Key switch or kill switch in OFF position.
● Low oil level.
● Quality of fuel (dirt, water, stale, mixture).
● SMART-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 plug(s).
● Flywheel key sheared.
● Fuel pump malfunction-vacuum hose clogged or
leaking.
● Interlock switch is engaged or faulty.
● Loose wires or connections that intermittently ground
ignition kill circuit.
● Low compression.
● Quality of fuel (dirt, water, stale, mixture).
● Weak spark.
Engine Will Not Crank
● Battery is discharged.
● Faulty electric starter or solenoid.
● Faulty key switch or ignition switch.
● Interlock switch is engaged or faulty.
● Loose wires or connections that intermittently ground
ignition kill circuit.
● Pawls not engaging in drive cup.
● Seized internal engine components.
Engine Runs But Misses
● Carburetor adjusted incorrectly.
● Engine overheated.
● Faulty spark plug(s).
● Ignition module(s) faulty or improperly gapped.
● Incorrect crankshaft position sensor air gap.
● Interlock switch is engaged or faulty.
● Loose wires or connections that intermittently ground
ignition kill circuit.
● Quality of fuel (dirt, water, stale, mixture).
● Spark plug lead(s) disconnected.
● Spark plug lead boot loose on plug.
● Spark plug lead loose.
Engine Will Not Idle
● Engine overheated.
● Faulty spark plug(s).
● Idle fuel adjusting needle(s) improperly set.
● Idle speed adjusting screw improperly set.
● Inadequate fuel supply.
● Low compression.
● Quality of fuel (dirt, water, stale, mixture).
● Restricted fuel tank cap vent.
Engine Overheats
● Cooling fan broken.
● Excessive engine load.
● Fan belt failed/off.
● Faulty carburetor.
● High crankcase oil level.
● Lean fuel mixture.
● Low cooling system fl uid level.
● Low crankcase oil level.
● Radiator, and/or cooling system components clogged,
restricted, or leaking.
● Water pump belt failed/broken.
● Water pump malfunction.
Engine Knocks
● Excessive engine load.
● Hydraulic lifter malfunction.
● Incorrect oil viscosity/type.
● Internal wear or damage.
● Low crankcase oil level.
● Quality of fuel (dirt, water, stale, mixture).
1662 690 02 Rev. DKohlerEngines.com
Troubleshooting
Engine Loses Power
● Dirty air cleaner element.
● Engine overheated.
● Excessive engine load.
● Restricted exhaust.
● Faulty spark plug(s).
● High crankcase oil level.
● Incorrect governor setting.
● Low battery.
● Low compression.
● Low crankcase oil level.
● Quality of fuel (dirt, water, stale, mixture).
Engine Uses Excessive Amount of Oil
● Loose or improperly torqued fasteners.
● Blown head gasket/overheated.
● Breather reed broken.
● Clogged, broken, or inoperative crankcase breather.
● Crankcase overfi lled.
● Incorrect oil viscosity/type.
● Worn cylinder bore.
● Worn or broken piston rings.
● Worn valve stems/valve guides.
Oil Leaks from Oil Seals, Gaskets
● Breather reed broken.
● Clogged, broken, or inoperative crankcase breather.
● Loose or improperly torqued fasteners.
● Piston blow by, or leaky valves.
● Restricted exhaust.
EXTERNAL ENGINE INSPECTION
NOTE: It is good practice to drain oil at a location away
from workbench. Be sure to allow ample time for
complete drainage.
Before cleaning or disassembling engine, make a
thorough inspection of its external appearance and
condition. This inspection can give clues to what
might be found inside engines (and cause) when it is
disassembled.
● Check for buildup of dirt and debris on crankcase,
cooling fi ns, grass screen, and other external surfaces.
Dirt or debris on these areas can cause overheating.
● Check for obvious fuel and oil leaks, and damaged
components. Excessive oil leakage can indicate a
clogged or inoperative breather, worn or damaged
seals or gaskets, or loose fasteners.
● Check air cleaner cover and base for damage or
indications of improper fi t and seal.
● Check air cleaner element. Look for holes, tears,
cracked or damaged sealing surfaces, or other
damage that could allow unfi ltered air into engine. A
dirty or clogged element could indicate insuffi cient or
improper maintenance.
● Check carburetor throat for dirt. Dirt in throat is further
indication that air cleaner was not functioning properly.
● Check if oil level is within operating range on dipstick.
If it is above, sniff for gasoline odor.
● Check condition of oil. Drain oil into a container; it
should fl ow freely. Check for metal chips and other
foreign particles.
Sludge is a natural by-product of combustion; a small
accumulation is normal. Excessive sludge formation
could indicate over rich fuel settings, weak ignition,
overextended oil change interval or wrong weight or
type of oil was used.
CLEANING ENGINE
WARNING
Cleaning Solvents can cause severe injury or
death.
Use only in well ventilated areas away from
ignition sources.
Carburetor cleaners and solvents are extremely
fl ammable. Follow cleaner manufacturer’s warnings
and instructions on its proper and safe use. Never use
gasoline as a cleaning agent.
After inspecting external condition of engine, clean
engine thoroughly before disassembly. Clean individual
components as engine is disassembled. Only clean
parts can be accurately inspected and gauged for wear
or damage. There are many commercially available
cleaners that will quickly remove grease, oil, and grime
from engine parts. When such a cleaner is used, follow
manufacturer’s instructions and safety precautions
carefully.
Make sure all traces of cleaner are removed before
engine is reassembled and placed into operation. Even
small amounts of these cleaners can quickly break down
lubricating properties of engine oil.
1762 690 02 Rev. DKohlerEngines.com
Troubleshooting
CRANKCASE VACUUM TEST
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.
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
manometer tube. Leave other tube open to
atmosphere. Check that water level in manometer is
at 0 line. Make sure pinch clamp is closed.
2. Start engine and run no-load high speed.
3. Open clamp and note water level in tube.
Level in engine side should be a minimum of 10.2
cm (4 in.) above level in open side.
If level in engine side is less than specifi ed (low/no
vacuum), or level in engine side is lower than level in
open side (pressure), check for conditions in table
below.
4. Close pinch clamp before stopping engine.
Keep hands, feet, hair, and clothing away from all
moving parts to prevent injury. Never operate engine
with covers, shrouds, or guards removed.
To test crankcase vacuum with vacuum/pressure gauge:
1. Remove dipstick or oil fi ll plug/cap.
2. Install adapter into oil fi ll//dipstick tube opening,
3. Run engine and observe gauge reading.
Analog tester–needle movement to left of 0 is a
Digital tester–depress test button on top of tester.
Crankcase vacuum should be a minimum of 10.2 cm
Rotating Parts can cause severe injury.
Stay away while engine is in operation.
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.
vacuum, and movement to right indicates a pressure.
(4 in.) of water. If reading is below specifi cation, or if
pressure is present, check table below for possible
causes and conclusions.
WARNING
ConditionConclusion
Crankcase breather clogged or inoperative.NOTE: If breather is integral part of valve cover and
cannot be serviced separately, replace valve
cover and recheck pressure.
Disassemble breather, clean parts thoroughly, check
sealing surfaces for fl atness, reassemble, and recheck
pressure.
Seals and/or gaskets leaking. Loose or improperly torque
fasteners.
Piston blow by or leaky valves (confi rm by inspecting
components).
Replace all worn or damaged seals and gaskets. Make
sure all fasteners are tightened securely. Use appropriate
torque valves and sequences when necessary.
Recondition piston, rings, cylinder bore, valves and
valves guides.
or replace as needed. Repair or replace any other
damaged/restricted muffl er or exhaust system parts.
1862 690 02 Rev. DKohlerEngines.com
Troubleshooting
COMPRESSION TEST
For Command Twins:
A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s)
before removing them. Be sure choke is off, and throttle is wide open during test. Compression should be at least 160
psi and should not vary more than 15% between cylinders.
All other models:
These engines are equipped with an automatic compression release (ACR) mechanism. It is diffi cult to obtain an
accurate compression reading because of ACR mechanism. As an alternative, use cylinder leakdown test described
below.
CYLINDER LEAKDOWN TEST
A cylinder leakdown test can be a valuable alternative to a compression test. By pressurizing combustion chamber
from an external air source you can determine if valves or rings are leaking, and how badly.
Cylinder leakdown tester is a relatively simple, inexpensive leakdown tester for small engines. This tester includes a
quick-connect for attaching adapter hose and a holding tool.
1. Run engine for 3-5 minutes to warm it up.
2. Remove spark plug(s) and air fi lter from engine.
3. Rotate crankshaft until piston (of cylinder being tested) is at top dead center (TDC) of compression stroke. Hold
engine in this position while testing. Holding tool supplied with tester can be used if PTO end of crankshaft is
accessible. Lock holding tool onto crankshaft. Install a 3/8 in. breaker bar into hole/slot of holding tool, so it is
perpendicular to both holding tool and crankshaft PTO.
If fl ywheel end is more accessible, use a breaker bar and socket on fl ywheel nut/screw to hold it in position. An
assistant may be needed to hold breaker bar during testing. If engine is mounted in a piece of equipment, it may
be possible to hold it by clamping or wedging a driven component. Just be certain that engine cannot rotate off of
TDC in either direction.
4. Install adapter into spark plug hole, but do not attach it to tester at this time.
6. Connect an air source of at least 50 psi to tester.
7. Turn regulator knob clockwise (increase direction) until gauge needle is in yellow set area at low end of scale.
8. Connect tester quick-connect to adapter hose. While fi rmly holding engine at TDC, gradually open tester valve.
Note gauge reading and listen for escaping air at combustion air intake, exhaust outlet, and crankcase breather.
ConditionConclusion
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 02 Rev. DKohlerEngines.com
Air Cleaner/Intake
AIR CLEANER
These systems are CARB/EPA certifi ed and components
should not be altered or modifi ed in any way.
Air Cleaner Components
G
B
AAir Cleaner HousingBEnd Cap
CElementDInner Element
EEjector AreaFInlet Screen
GRetaining ClipHFilter Minder
NOTE: Operating engine with loose or damaged air
cleaner components could cause premature
wear and failure. Replace all bent or damaged
components.
NOTE: Paper element cannot be blown out with
compressed air.
C
E
D
F
A
H
1. Unhook retaining clips and remove end cap(s).
2. Check and clean inlet screen (if equipped).
3. Pull air cleaner element out of housing and replace.
Check condition of inner element; replace when
dirty.
4. Check all parts for wear, cracks, or damage, and that
ejector area is clean.
5. Install new element(s).
6. Reinstall end cap(s) with dust ejector valve/screen
down; secure with retaining clips.
BREATHER TUBE
Ensure both ends of breather tube are properly
connected.
AIR COOLING
WARNING
Hot Parts can cause severe burns.
Do not touch engine while operating or just
after stopping.
Never operate engine with heat shields or guards
removed.
Proper cooling is essential. To prevent over heating,
clean screens, cooling fi ns, and other external surfaces
of engine. Avoid spraying water at wiring harness or any
electrical components. Refer to Maintenance Schedule.
62 690 02 Rev. DKohlerEngines.com20
Fuel System
Typical carbureted fuel system and related components
include:
● Fuel tank and valve.
● Fuel lines.
● In-line fuel fi lter.
● Fuel pump.
● Carburetor.
Fuel from tank is moved through in-line fi lter and fuel
lines by fuel pump. Fuel then enters carburetor fl oat bowl
and is drawn into carburetor body and mixed with air.
This fuel-air mixture is then burned in engine combustion
chamber.
FUEL RECOMMENDATIONS
Refer to Maintenance.
FUEL LINE
Low permeation fuel line must be installed on carbureted
Kohler Co. engines to maintain EPA and CARB
regulatory compliance.
FUEL SYSTEM TESTS
When engine starts hard or turns over but will not start, fuel system might be causing problems. Test fuel system by
performing following test.
1. Check for fuel in combustion chamber.
a. Disconnect and ground spark plug leads.
b. Close choke on carburetor.
c. Crank engine several times.
d. Remove spark plug and check for fuel at tip.
2. Check for fuel fl ow from tank to fuel pump.a. Remove fuel line from inlet fi tting of fuel pump.b. Hold line below bottom of tank. Open shut-off
valve (if equipped) and observe fl ow.
FUEL PUMP
Some engines use a pulse style fuel pump or optional
remote-mounted electric fuel pump assembly. Pumping
action of pulse style pumps is created by oscillation of
positive and negative pressures within crankcase. This
pressure is transmitted to pulse pump through rubber
hose connected between pump and crankcase. Pumping
action causes diaphragm on inside of pump to pull fuel
in on its downward stroke and to push it into carburetor
on its upward stroke. Two check valves prevent fuel from
going backward through pump.
Fuel Pump Replacement
NOTE: Make sure orientation of new pump is consistent
with removed pump. Internal damage may occur
if installed incorrectly.
To replace pulse pump follow these steps. Note
orientation of pump before removing.
1. Disconnect fuel lines from inlet, outlet, and pulse
fi ttings on fuel pump.
2. Remove screws and take off pump.
3. Connect pulse line to new fuel pump and make sure
opposite end is properly connected to oil fi lter
housing fi tting.
4. Attach new fuel pump using screws. Torque screws
to 8.0-12.1 N·m (71-107 in. lb.) into new holes, or
6.0-9.0 N·m (53-80 in. lb.) into used holes.
5. Reconnect fuel lines to inlet and outlet fi ttings and
secure with clamps.
3. Check operation of fuel pump.
a. Remove fuel line from inlet fi tting of carburetor.b. Crank engine several times and observe fl ow.
ConditionConclusion
Fuel at tip of spark plug.Fuel is reaching combustion chamber.
No fuel at tip of spark plug.Check fuel fl ow from fuel tank (step 2).
Fuel fl ows from fuel line.Check for faulty fuel pump (step 3).
No fuel fl ow from fuel line.Check fuel tank cap vent, fuel pickup screen, in-line
Fuel line condition.Check for a clogged fuel line. If fuel line is unobstructed,
If fuel pump is working, check for faulty carburetor. Refer
to Carburetor.
fi lter, shut-off valve, and fuel line. Correct any observed
problem and reconnect line.
check for overfi lled crankcase and/or oil in pulse line. If
checks don't reveal cause of problem, replace pump.
2162 690 02 Rev. DKohlerEngines.com
Fuel System
CARBURETOR
WARNING
Explosive Fuel can cause fi res and severe
burns.
Do not fi ll fuel tank while engine is hot or
running.
Two-Barrel Carburetor Components
D
E
F
G
B
AF
AE
C
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.
H
AB
AA
I
A
K
U
AC
AD
L
Z
J
T
Q
R
V
X
Carburetor Body
A
Subassembly
F
K
PSealing WasherQFloatRPinSScrewTFloat Clip
U
ZChoke Dust Cap AAChoke ShaftABSpringACBushingADChoke Lever
AEChoke PlateAF
Retaining
Washer
O-Ring (Fuel
Bowl-Upper)
Float Valve/
Inlet Needle
Y
B
G
L
V
W
Idle Speed
Screw
Slow Jet-
Right Side
O-Ring (Fuel
Bowl-Lower)
Main Nozzle-
Right Side
Choke Plate
Screw
M
S
C
H
MDrain ScrewNBowl ScrewOFuel Solenoid
W
Idle Speed
Spring
Slow Jet-
Left Side
Main Nozzle-
Left Side
DScrewEGround Lead
I
X
P
O-Ring
(Slow Jet)
Main Jet-
Right Side
N
O
JFuel Bowl
Y
Main Jet-
Left Side
2262 690 02 Rev. DKohlerEngines.com
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