Kohler CS10 User manual

SERVICE MANUAL
COMMAND PRO CS SERIES 4-12 HP
HORIZONTAL CRANKSHAFT

Contents
Section 1. Safety and General Information ............................................................................
Section 2. Special Tools...........................................................................................................
Section 3. Troubleshooting .....................................................................................................
Section 4.Air Cleaner and Air Intake System .........................................................................
Section 5. Fuel System and Governor ....................................................................................
Section 6. Lubrication System ................................................................................................
Section 7. Retractable Starter..................................................................................................
Section 8. Electrical System and Components......................................................................
Section 9. Disassembly............................................................................................................
Section 10. Internal Components............................................................................................
Section 11. Reassembly...........................................................................................................
1
2
3
4
5
6
7
8
9
10
11

1.1
Section 1
Safety and General Information
1
Section 1
Safety and General Information
CS4-12
For Your Safety!
These precautions should be followed at all times. Failure to follow these precautions could result
in injury to yourself and others.
Safety Precautions
To insure safe operations please read the following statements and understand their meaning.
Also refer to your equipment owner's manual for other important safety information.This manual
contains safety precautions which are explained below. Please read carefully.
WARNING
Warning is used to indicate the presence of a hazard that can cause severe personal injury,
death, or substantial property damage if the warning is ignored.
CAUTION
Caution is used to indicate the presence of a hazard that will or can cause minor personal injury
or property damage if the warning is ignored.
NOTE
Note is used to notify people of installation, operation, or maintenance information that is
important but not hazard-related.
Hot Parts!
Engine components can get
extremely hot from operation. To
prevent severe burns, do not touch
these areas while the engine is
running—or immediately after it is
turned off. Never operate the
engine with heat shields or guards
removed.
Rotating Parts!
Keep hands, feet, hair, and clothing
away from all moving parts to
prevent injury. Never operate the
engine with covers, shrouds, or
guards removed.
Rotating Parts can cause severe
injury.
Stay away while engine is in
operation.
WARNING
Hot Parts can cause severe burns.
Do not touch engine while operating
or just after stopping.
WARNING
Accidental Starts!
Disabling engine.Accidental starting
can cause severe injury or death.
Before working on the engine or
equipment, disable the engine as
follows: 1) Disconnect the spark
plug lead(s). 2) Disconnect negative
(-) battery cable from battery.
Accidental Starts can cause severe
injury or death.
Disconnect and ground spark plug
lead before servicing.
WARNING

1.2
Section 1
Safety and General Information
Lethal Exhaust Gases!
Engine exhaust gases contain
poisonous carbon monoxide.
Carbon monoxide is odorless,
colorless, and can cause death if
inhaled.Avoid inhaling exhaust
fumes, and never run the engine in
a closed building or confined area.
Explosive Gas!
Batteries produce explosive
hydrogen gas while being charged.
To prevent a fire or explosion,
charge batteries only in well
ventilated areas. Keep sparks, open
flames, and other sources of
ignition away from the battery at all
times. Keep batteries out of the
reach of children. Remove all
jewelry when servicing batteries.
Before disconnecting the negative (-
) ground cable, make sure all
switches are OFF. If ON, a spark
will occur at the ground cable
terminal which could cause an
explosion if hydrogen gas or
gasoline vapors are present.
Flammable Solvents!
Carburetor cleaners and solvents
are extremely flammable. Keep
sparks, flames, and other sources
of ignition away from the area.
Follow the cleaner manufacturer’s
warnings and instructions on its
proper and safe use. Never use
gasoline as a cleaning agent.
Spring Under Tension!
Retractable starters contain a
powerful, recoil spring that is under
tension. Always wear safety
goggles when servicing retractable
starters and carefully follow
instructions in the "Retractable
Starter" Section 7 for relieving
spring tension.
Electrical Shock!
Never touch electrical wires or
components while the engine is
running. They can be sources of
electrical shock.
Explosive Fuel!
Gasoline is extremely flammable
and its vapors can explode if
ignited. Store gasoline only in
approved containers, in well
ventilated, unoccupied buildings,
away from sparks or flames. Do not
fill the fuel tank while the engine is
hot or running, since spilled fuel
could ignite if it comes in contact
with hot parts or sparks from
ignition. Do not start the engine
near spilled fuel. Never use
gasoline as a cleaning agent.
Cleaning Solvents can cause
severe injury or death.
Use only in well ventilated areas
away from ignition sources.
WARNING
WARNING
Explosive Gas can cause fires and
severe acid burns.
Charge battery only in a well
ventilated area. Keep sources of
ignition away.
Carbon Monoxide can cause
severe nausea, fainting or death.
Do not operate engine in closed or
confined area.
WARNING
Uncoiling Spring can cause severe
injury.
Wear safety goggles or face
protection when servicing retractable
starter.
WARNING
Electrical Shock can cause injury.
Do not touch wires while engine is
running.
CAUTION
WARNING
Explosive Fuel can cause fires and
severe burns.
Stop engine before filling fuel tank.

1.3
Section 1
Safety and General Information
1
Engine Identification Numbers
When ordering parts, or in any communication
involving an engine, always give the Model,
Specification, and Serial Numbers of the engine.
The engine identification numbers appear on a decal
(or decals) affixed to the engine shrouding. See Figure
1-1.An explanation of these numbers is shown in
Figure 1-2.
Model Designation
Model CS6ST for example: C designates Command
engine, S designates slanted cylinder configuration,
and 6 designates horsepower. Asuffix letter
designates a specific version as follows: Figure 1-1. Engine Identification Decal Location.
Identification Decal
A. Model No.
Command Engine
Slanted Cylinder
Horsepower
4 = 4 HP
6 = 6 HP
8.5 = 8.5 HP
10 = 10 HP
12 = 12 HP
Suffix Designates
T Retractable Start
S Electric Start
G Tapered Crankshaft
P Threaded Crankshaft
R Gear Reduction (2:1 or 6:1)
Figure 1-2. Explanation of Engine Identification Numbers.
#NOTE: CS8.5 engines have been produced in two different specification series, 92xxxx and 95xxxx. The design
features of 92xxxx spec. no. engines are identical to CS10 and CS12 engines, and share the same
service procedures. The 95xxxx spec. no. engines incorporate certain design differences from the
92xxxx spec. no. series. All service and repair information unique to the 95xxxx spec. no. series will be
listed and covered separately.
C S 6 ST
Variation of
Basic Engine
B. Spec. No.
Engine Model Code
Code Model
90 CS4
91 CS6
92 CS8.5#300 cc
93 CS10
94 CS12
95 CS8.5#250 cc
911509
C. Serial No.
Year Manufactured Code
Code Year
28 1998
29 1999
30 2000
Factory Code
28 23701265
A
B
C
IMPORTANT ENGINE INFORMATION
THIS ENGINE MEETS U.S. EPA
PHASE 1 AND 2000-2001
CALIFORNIA EMISSION CONTROL
REGULATIONS FOR SORE*
FAMILY
MODEL NO. CS6ST
SPEC. NO. 911509
DISPL (CC)
SERIAL NO. 2823701265
REFER TO OWNER'S MANUAL FOR
SAFETY, MAINTENANCE SPECS,
AND ADJUSTMENTS. FOR SALES
AND SERVICE IN US/CANADA CALL:
1-800-544-2444
KOHLER CO. KOHLER, WI USA
(Ref.***-*******)
*Small Off-Road Engines.

1.4
Section 1
Safety and General Information
Oil Recommendations
Using the proper type and weight of oil in the
crankcase is extremely important, as is checking oil
daily and changing oil regularly. Failure to use the
correct oil or using dirty oil, causes premature engine
wear and failure.
Oil Type
Use high quality detergent oil of API (American
Petroleum Institute) service class SG, SH, SJ or
higher. Select the viscosity based on the air
temperature at the time of operation as shown below.
Figure1-3. Viscosity Grades Table.
NOTE: Using other than service class SG, SH, SJ or
higher oil or extending oil change intervals
longer than recommended can cause engine
damage.
Alogo or symbol on oil containers identifies theAPI
service class and SAE viscosity grade. See Figure
1-4.
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well ventilated, unoccupied buildings,
away from sparks or flames. Do not fill the fuel tank
while the engine is hot or running, since spilled fuel
could ignite if it comes in contact with hot parts or
sparks from ignition. Do not start the engine near
spilled fuel. Never use gasoline as a cleaning agent.
General Recommendations
Purchase gasoline in small quantities and store in
clean, approved containers.Acontainer with a capacity
of 2 gallons or less with a pouring spout is
recommended. Such a container is easier to handle
and helps eliminate spillage during refueling.
Do not use gasoline left over from the previous
season, to minimize gum deposits in your fuel system
and to insure easy starting.
Do not add oil to the gasoline.
Do not overfill the fuel tank. Leave room for the fuel to
expand.
Fuel Type
For best results, use only clean, fresh, unleaded
gasoline with a pump sticker octane rating of 87 or
higher. In countries using the Research method, it
should be 90 octane minimum.
Unleaded gasoline is recommended, as it leaves less
combustion chamber deposits. Leaded gasoline may
be used in areas where unleaded is not available and
exhaust emissions are not regulated. Be aware
however, that the cylinder head will require more
frequent service.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded
gasoline by volume) is approved as a fuel for Kohler
engines. Other gasoline/alcohol blends are not
approved.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to maximum of 15% MTBE by
volume) are approved as a fuel for Kohler engines.
Other gasoline/ether blends are not approved.
Figure 1-4. Oil Container Logo.
Refer to Section 6-‘‘Lubrication System’’ for detailed oil
check and oil change procedures.

1.5
Section 1
Safety and General Information
1
Maintenance Instructions
WARNING: Accidental Starts!
Disabling engine. Accidental starting can cause severe injury or death. Before working on the engine or
equipment, disable the engine as follows: 1) Disconnect the spark plug lead (s). 2) Disconnect negative (-)
battery cable from battery.
Maintenance Schedule
These required maintenance procedures should be performed at the frequency stated in the table. They should
also be included as part of any seasonal tune-up.
Daily or Before
Starting Engine
Maintenance RequiredFrequency • Fill fuel tank.
• Check oil level.
• Check air cleaner for dirty, loose, or damaged parts.1
• Check air intake and cooling areas, clean as necessary.1
Refer to:
Section 5
Section 6
Section 4
Section 4
• Service precleaner element. Replace if necessary.1
Every 25 Hours Section 4
• Change oil.
• Replace air cleaner element.1
• Remove cooling shrouds and clean cooling areas.1
• Check all fittings and fasteners.
• Clean fuel shut-off valve filter. Replace if necessary.
• Check muffler screen/spark arrestor. Clean/replace if necessary.
• Check spark plug condition and gap. Replace if necessary.
Every 100 Hours
• Check and adjust valve clearance when engine is cold.2
• Check and adjust idle speed.2
• Service starter motor drive, if so equipped.2
• Have combustion chamber decarbonized.2
Annually or
Every 300 Hours
Section 6
Section 4
Section 4
Section 1
Section 5
Section 8
Section 11
Section 5
Section 7
¹Perform these maintenance procedures more frequently under extremely dusty, dirty conditions.
²Have a Kohler Engine Service Dealer perform this service.
Storage
If the engine will be out of service for two months or
more, use the following storage procedure:
1. Clean the exterior surfaces of the engine.
2. Change the oil while the engine is still warm from
operation. See ‘‘Change Oil’’on page 6.2.
3. The fuel system must be completely emptied, or
the gasoline must be treated with a stabilizer to
prevent deterioration. If you choose to use a
stabilizer, follow the manufacturers
recommendations, and add the correct amount
for the capacity of the fuel system. Fill the fuel
tank with clean, fresh gasoline. Run the engine for
2-3 minutes to get stabilized fuel into the
carburetor.
To empty the system, run the engine until the tank
and system are empty.
4. Remove the spark plug.Add one tablespoon of
engine oil into the spark plug hole. Install the plug,
but do not connect the plug lead. Crank the
engine two or three revolutions and then turn it up
against compression (when highest pull force or
cranking force is required).
5. Store the engine in a clean, dry place.
• Service solid foam element. Replace if necessary.1Section 4Every 50 Hours

1.6
Section 1
Safety and General Information
Figure 1-5. Typical Engine Dimensions CS4 and CS6.
Dimensions in millimeters.
Inch equivalents shown in ( ).
373.00
(14.685)
66.00
(2.598) 162.00
(6.378)
5/16-24 [qty. 5]
14 mm (.551) deep
106.00
(4.173)
30.00
(1.181)
347.00
(13.661)
321.50 (Straight PTO)
(12.657)
143.00
(5.630)
100.00
(3.937) 162.00
(6.378)
Spark Plug
Oil Fill
Oil Drain
Plug
Mounting Face
5.00
(.197)
44.50
(1.752)
80.00
(3.150)
37.00
(1.457)
384.25
(15.128)
145.25
(5.719) 380.03
(14.962)
9.0 (.354) dia. [qty. 2]
9.0x14.0 (.354x.551) slot
[qty.2]

1.7
Section 1
Safety and General Information
1
Figure 1-6. Typical Engine Dimensions CS8.5 (spec. 92xxxx), CS10, and CS12.
Dimensions in millimeters.
Inch equivalents shown in ( ).
454.00
(17.874)
445.85
(17.553)
156.68
(6.168) 45°
45°
30° 30°
423.50
(16.673)
70.00
(2.756)
165.10 (6.500)
dia.
146.08
(5.751) dia.
103.00
(4.055)
195.50
(7.697)
90.50
(3.563)
110.00
(4.331) dia.
127.00
(5.000) dia.
133.50
(5.256)
452.90
(17.831)
417.50 (Straight PTO)
(16.437)
187.50
(7.382)
118.34
(4.659) 205.00 (8.071)
99.00
(3.898)
Spark Plug
Oil Fill
Oil Drain Plug
Mounting Face
16.00
(.630)
37.00
(1.457)
62.00
(2.441) 102.00 (4.016)
65.00
(2.559)
152.00
(5.984) 298.00
(11.732)
5/16-24 [qty. 4]
18 mm (.709) deep
3/8-16 [qty. 4]
18 mm (.709) deep
5/16-24 [qty. 2] 18 mm
(.709) deep
11.00 (.433) dia. [qty. 2]
11.00x27 (.433x1.063) slot
[qty. 2]

1.8
Section 1
Safety and General Information
Figure 1-7. Typical Engine Dimensions CS8.5 (spec. 95xxxx).
431.00
(16.968)
156.00
(6.142)
428.00
(16.850)
410.00
(16.142)
133.50
(5.256)
90.50
(3.563) 103.00 (4.055)
195.50
(7.697)
424.00
(16.693)
70.00
(2.756)
165.1 (6.50)
110 (4.33)
5/16-24 18 mm (.709) deep [qty. 2]
5/16-24 18 mm (.709) deep [qty. 4]
3/8-16 18 mm (.709) deep
[qty. 4]
146.08 (5.78)
380.00
(14.961)
183.00
(7.205)94.5
(3.720)
16.00 (.630)
57.50 (2.264) 96.00
(3.780)
59.00 (2.323)
11.00x27.00
(.433x1.063)
slotted hole
[qty. 2]
11 (.433) hole [qty. 2]
37.00 (1.457)
C
L
Dimensions in millimeters.
Inch equivalents shown in ( ).

1.9
Section 1
Safety and General Information
1
Description CS4-12
General Specifications
Power (@ 3600 RPM, corrected to SAE J1349)
CS4.................................................................................................2.9 kW (4 HP)
CS6.................................................................................................4.47 kW (6 HP)
CS8.5 (spec. 95xxxx)......................................................................5.40 kW (8.5 HP)
CS8.5 (spec. 92xxxx)......................................................................6.33 kW (8.5 HP)
CS10...............................................................................................7.45 kW (10 HP)
CS12...............................................................................................8.95 kW (12 HP)
Peak Torque
CS4 (@ 2000 RPM) ........................................................................7.6 N·m (5.6 ft. lb.)
CS6 (@ 2000 RPM) ........................................................................10.8 N·m (8 ft. lb.)
CS8.5 (spec. 95xxxx @ 2400 RPM)................................................16.5 N·m (12.1 ft. lb.)
CS8.5 (spec. 92xxxx @ 2000 RPM)................................................19.66 N·m (14.5 ft. lb.)
CS10 (@ 2000 RPM) ......................................................................19.66 N·m (14.5 ft. lb.)
CS12 (@ 2000 RPM) ......................................................................22.6 N·m (16.7 ft. lb.)
Bore
CS4.................................................................................................56.0 mm (2.20 in.)
CS6.................................................................................................66.0 mm (2.60 in.)
CS8.5 (spec. 95xxxx)......................................................................75.0 mm (2.95 in.)
CS8.5 (spec. 92xxxx)......................................................................78.0 mm (3.07 in.)
CS10...............................................................................................78.0 mm (3.07 in.)
CS12...............................................................................................85.0 mm (3.35 in.)
Stroke
CS4,CS6 .........................................................................................50.0 mm (1.97 in.)
CS8.5 (spec. 95xxxx)......................................................................57.0 mm (2.44 in.)
CS8.5 (spec. 92xxxx)......................................................................63.0 mm (2.48 in.)
CS10-12..........................................................................................63.0 mm (2.48 in.)
Displacement
CS4.................................................................................................123 cc (7.50 cu. in.)
CS6.................................................................................................171 cc (10.43 cu. in.)
CS8.5 (spec. 95xxxx)......................................................................251 cc (15.30 cu. in.)
CS8.5 (spec. 92xxxx)......................................................................301 cc (18.37 cu. in.)
CS10...............................................................................................301 cc (18.37 cu. in.)
CS12...............................................................................................357 cc (21.79 cu. in.)
Compression Ratio
CS4.................................................................................................8.3:1
CS6.................................................................................................8.5:1
CS8.5 (spec. 95xxxx)......................................................................8.3:1
CS8.5 (spec. 92xxxx)......................................................................8.1:1
CS10-12..........................................................................................8.1:1
Weight (Approx.)
CS4,CS6 .........................................................................................15.4 kg (35 lb.)
CS8.5 (spec. 95xxxx)......................................................................26 kg (57.2 lb.)
CS8.5 (spec. 92xxxx)......................................................................31.9 kg (70.5 lb.)
CS10-12..........................................................................................31.9 kg (70.5 lb.)

1.10
Section 1
Safety and General Information
Oil Capacity (Approx.)
CS4,CS6 .........................................................................................0.6 L (0.64 U.S. qt.)
CS8.5 (spec. 95xxxx)......................................................................1.0 L (1.1 U.S. qt.)
CS8.5 (spec. 92xxxx)......................................................................1.1 L (1.2 U.S. qt.)
CS10-12..........................................................................................1.1 L (1.2 U.S. qt.)
Fuel Tank Capacity
CS4,CS6 .........................................................................................3.9 L (4.1 U.S. qt.)
CS8.5 (spec. 95xxxx)......................................................................6.0 L (6.3 U.S. qt.)
CS8.5 (spec. 92xxxx)......................................................................6.9 L (7.3 U.S. qt.)
CS10-12..........................................................................................6.9 L (7.3 U.S. qt.)
Angle of Operation – Maximum (At Full Oil Level)All Directions............20°
Air Cleaner
Base Bolt Torque ...................................................................................5-8 N·m (44-71 in. lb.)
Base Nut Torque
CS4,CS6 .........................................................................................5-8 N·m (44-71 in. lb.)
CS8.5 (spec. 95xxxx)......................................................................5-8 N·m (44-71 in. lb.)
CS8.5 (spec. 92xxxx)......................................................................10-12 N·m (88-106 in. lb.)
CS10-12..........................................................................................10-12 N·m (88-106 in. lb.)
Camshaft
EndPlay ................................................................................................0.05 mm (0.0020 in.)
Bore I.D. – Max. Wear Limit
CS4,CS6 .........................................................................................14.95 mm (0.583 in.)
CS8.5-12.........................................................................................15.95 mm (0.627 in.)
Camshaft Bearing Surface O.D. – Max. Wear Limit
CS4,CS6 .........................................................................................15.05 mm (0.592 in.)
CS8.5-12.........................................................................................16.05 mm (0.649 in.)
Carburetor
Fuel Bowl Retaining Screw Torque
CS4,CS6 .........................................................................................7 N·m (62 in. lb.)
CS8.5-12.........................................................................................9 N·m (79 in. lb.)
Throttle/Choke Plate Screws Torque .....................................................1.5-2.5 N·m (13-22 in. lb.)
Connecting Rod
Connecting Rod Fastener Torque
CS4,CS6 .........................................................................................12 N·m (106 in. lb.)
CS8.5 (spec. 95xxxx)......................................................................12 N·m (106 in. lb.)
CS8.5 (spec. 92xxxx)......................................................................20 N·m (177 in. lb.)
CS10-12..........................................................................................20 N·m (177 in. lb.)
Connecting Rod-to-Crankpin Running Clearance
New.................................................................................................0.016/0.046 mm (0.0006/0.0018 in.)
Max. Wear Limit ..............................................................................0.1 mm (0.004 in.)

1.11
Section 1
Safety and General Information
1
Connecting Rod-to-Crankpin Side Clearance
CS4,CS6 .........................................................................................0.2/0.6 mm (0.008/0.024 in.)
CS8.5 (spec. 95xxxx)......................................................................0.2/0.6 mm (0.008/0.024 in.)
CS8.5 (spec. 92xxxx)......................................................................0.2/0.65 mm (0.0079/0.0256 in.)
CS10-12..........................................................................................0.2/0.65 mm (0.0079/0.0256 in.)
Connecting Rod-to-Piston Pin Running Clearance ................................0.006/0.025 mm (0.0002/0.0001 in.)
Piston Pin End I.D.
NewCS4,CS6...................................................................................16.006/16.020 mm (0.6301/0.6307 in.)
CS8.5 (spec. 95xxxx) ...............................................................18.006/18.020 mm (0.7089/0.7094 in.)
CS8.5 (spec. 92xxxx) ...............................................................20.006/20.020 mm (0.7876/0.7882 in.)
CS10-12 ...................................................................................20.006/20.020 mm (0.7876/0.7882 in.)
Max. Wear Limit
CS4,CS6...................................................................................16.10 mm (0.634 in.)
CS8.5 (95xxxx) .........................................................................18.10 mm (0.713 in.)
CS8.5 (92xxxx) .........................................................................20.10 mm (0.791 in.)
CS10-12 ...................................................................................20.10 mm (0.791 in.)
Connecting Rod Journal End I.D.
NewCS4,CS6...................................................................................28.000/28.015 mm (1.1023/1.1029 in.)
CS8.5 (spec. 95xxxx) ...............................................................32.000/32.015 mm (1.2598/1.2604 in.)
CS8.5 (spec. 92xxxx) ...............................................................36.000/36.015 mm (1.4173/1.4179 in.)
CS10-12 ...................................................................................36.000/36.015 mm (1.4173/1.4179 in.)
Max. Wear Limit
CS4,CS6...................................................................................28.115 mm (1.1069 in.)
CS8.5 (95xxxx) .........................................................................32.115 mm (1.2644 in.)
CS8.5 (92xxxx) .........................................................................36.115 mm (1.4219 in.)
CS10-12 ...................................................................................36.115 mm (1.4219 in.)
Crankcase
Closure Plate Fastener Torque
CS4,CS6 .........................................................................................22 N·m (195 in. lb.)
CS8.5-12.........................................................................................30 N·m (265 in. lb.)
Oil Drain Plugs Torque
CS4,CS6 .........................................................................................17 N·m (150 in. lb.)
CS8.5-12.........................................................................................20 N·m (177 in. lb.)
Crankshaft
End Play (Free) .....................................................................................0.04 mm (0.0015 in.)
End Play (Threaded Pump Shaft Models Only) .....................................0.0/0.2 mm (0.0/0.007 in.)

1.12
Section 1
Safety and General Information
Flywheel End Main Bearing Journal O.D.
NewCS4,CS6...................................................................................52 mm (2.047 in.)
CS8.5 (spec. 95xxxx) ...............................................................52 mm (2.047 in.)
CS8.5 (spec. 92xxxx) ...............................................................80 mm (3.149 in.)
CS10-12 ...................................................................................80 mm (3.149 in.)
Max. Wear Limit
CS4,CS6...................................................................................52.05 mm (2.0492 in.)
CS8.5 (spec. 95xxxx) ...............................................................52.05 mm (2.0492 in.)
CS8.5 (spec. 92xxxx) ...............................................................80.05 mm (3.1515 in.)
CS10-12 ...................................................................................80.05 mm (3.1515 in.)
PTO End Main Bearing Journal O.D.
NewCS4,CS6...................................................................................52 mm (2.047 in.)
CS8.5 (spec. 95xxxx) ...............................................................52 mm (2.047 in.)
CS8.5 (spec. 92xxxx) ...............................................................72 mm (2.834 in.)
CS10-12 ...................................................................................72 mm (2.834 in.)
Max. Wear Limit
CS4,CS6...................................................................................52.05 mm (2.0492 in.)
CS8.5 (spec. 95xxxx) ...............................................................52.05 mm (2.0492 in.)
CS8.5 (spec. 92xxxx) ...............................................................72.05 mm (2.836 in.)
CS10-12 ...................................................................................72.05 mm (2.836 in.)
Connecting Rod Journal O.D.
NewCS4,CS6...................................................................................27.969/27.984 mm (1.011/1.017 in.)
CS8.5 (spec. 95xxxx) ...............................................................31.969/31.984 mm (1.2586/1.2592 in.)
CS8.5 (spec. 92xxxx) ...............................................................35.969/35.984 mm (1.4161/1.4167 in.)
CS10-12 ...................................................................................35.969/35.984 mm (1.4161/1.4167 in.)
Max. Wear Limit
CS4,CS6...................................................................................27.9 mm (1.098 in.)
CS8.5 (spec. 95xxxx) ...............................................................31.9 mm (1.2559 in.)
CS8.5 (spec. 92xxxx) ...............................................................35.9 mm (1.4134 in.)
CS10-12 ...................................................................................35.9 mm (1.4134 in.)
Crankshaft
Runout (Either End) ........................................................................0.02 mm (0.0008 in.)
Limit (Either End) ............................................................................0.04 mm (0.0016 in.)

1.13
Section 1
Safety and General Information
1
Cylinder Bore
Cylinder Bore I.D.
NewCS4 ..........................................................................................56.005/56.015 mm (2.2049/2.2053 in.)
CS6 ..........................................................................................66.005/66.015 mm (2.5986/2.5990 in.)
CS8.5 (spec. 95xxxx) ...............................................................75.005/75.015 mm (2.9530/2.9533 in.)
CS8.5 (spec. 92xxxx) ...............................................................78.00/78.02 mm (3.0709/3.0717 in.)
CS10 ........................................................................................78.00/78.02 mm (3.0709/3.0717 in.)
CS12 ........................................................................................85.00/85.02 mm (3.3465/3.3472 in.)
Max. Wear Limit
CS4 ..........................................................................................56.15 mm (2.211 in.)
CS6 ..........................................................................................66.15 mm (2.604 in.)
CS8.5 (spec. 95xxxx) ...............................................................75.15 mm (2.959 in.)
CS8.5 (spec. 92xxxx) ...............................................................78.65 mm (3.096 in.)
CS10 ........................................................................................78.65 mm (3.096 in.)
CS12 ........................................................................................85.65 mm (3.372 in.)
Max. Out-of-Round .........................................................................0.05 mm (0.002 in.)
Cylinder Head
Cylinder Head Bolt Torque
CS4,CS6 .........................................................................................20 N·m (177 in. lb.)
CS8.5-12.........................................................................................50 N·m (36 ft. lb.)
Max. Out-of-Flatness.............................................................................0.1 mm (0.004 in.)
Electric Starter
Thru Bolt (Case) Torque
CS8.5-12.........................................................................................5.3 N·m (47.7 in. lb.)
Mounting Bolts (To Block) Torque
CS8.5-12.........................................................................................16 N·m (141 in. lb.)
Flywheel
Flywheel Retaining ScrewTorque
CS4,CS6 .........................................................................................65 N·m (48 ft. lb.)
CS8.5 (spec. 95xxxx)......................................................................65 N·m (48 ft. lb.)
CS8.5 (spec. 92xxxx)......................................................................120 N·m (85 ft. lb.)
CS10-12..........................................................................................120 N·m (85 ft. lb.)
Fuel Tank
Fuel Tank Fastener Screws Torque .......................................................8-12 N·m (71-106 in. lb.)
Ignition
Spark Plug Type
NGK ................................................................................................BPR4ES (13/16 hex.)
Champion®......................................................................................RN14YC (13/16 hex.)
Champion®......................................................................................RC14YC
(5/8 hex., Kohler Part No. 66 132 01-S)
Spark Plug Gap .....................................................................................0.76 mm (0.030 in.)
Spark Plug Torque .................................................................................20 N·m (14.7 ft. lb./177 in. lb.)
Ignition ModuleAir Gap .........................................................................0.4/0.6 mm (0.015/0.023 in.)

1.14
Section 1
Safety and General Information
Ignition Module Mounting Screws Torque ..............................................10 N·m (88 in. lb.)
Stator Mounting Screw Torque
CS8.5-12.........................................................................................5-8 N·m (44-70 in. lb.)
Muffler
Muffler Torque (Flange Nuts & Bracket Bolts)
CS4,CS6 .........................................................................................8-12 N·m (71-106 in. lb.)
CS8.5-12.........................................................................................18-22 N·m (159-195 in. lb.)
Oil Sentry™
Oil Sentry™ Float Switch Torque ............................................................10 N·m (88 in. lb.)
Piston, Piston Rings, and Piston Pin
Piston-to-Piston Pin Clearance
CS4,CS6 .........................................................................................0.002/0.018 mm (0.0001/0.0007 in.)
CS8.5-12.........................................................................................0.004/0.020 mm (0.0002/0.0008 in.)
Piston Pin Bore I.D.
NewCS4,CS6...................................................................................16.002/16.013 mm (0.6300/0.6304 in.)
CS8.5 (spec. 95xxxx) ...............................................................18.004/18.015 mm (0.7088/0.7093 in.)
CS8.5 (spec. 92xxxx) ...............................................................20.004/20.015 mm (0.7876/0.7880 in.)
CS10-12 ...................................................................................20.004/20.015 mm (0.7876/0.7880 in.)
Max. Wear Limit
CS4,CS6...................................................................................16.03 mm (0.6311 in.)
CS8.5 (spec. 95xxxx) ...............................................................18.03 mm (0.7098 in.)
CS8.5 (spec. 92xxxx) ...............................................................20.03 mm (0.7886 in.)
CS10-12 ...................................................................................20.03 mm (0.7886 in.)
Piston Pin O.D.
NewCS4,CS6...................................................................................15.995/16.000 mm (0.6297/0.6299 in.)
CS8.5 (spec. 95xxxx) ...............................................................17.995/18.000 mm (0.7084/0.7086 in.)
CS8.5 (spec. 92xxxx) ...............................................................19.995/20.000 mm (0.7872/0.7874 in.)
CS10-12 ...................................................................................19.995/20.000 mm (0.7872/0.7874 in.)
Max. Wear Limit
CS4,CS6...................................................................................15.98 mm (0.6291 in.)
CS8.5 (spec. 95xxxx) ...............................................................17.98 mm (0.7079 in.)
CS8.5 (spec. 92xxxx) ...............................................................19.98 mm (0.7866 in.)
CS10-12 ...................................................................................19.98 mm (0.7866 in.)
Top Compression Ring-to-Groove Side Clearance ................................0.04/0.08 mm (0.0016/0.003 in.)
Middle Compression Ring-to-Groove Side Clearance
CS4,CS6 .........................................................................................0.02/0.06 mm (0.0008/0.0024 in.)
CS8.5-12.........................................................................................0.03/0.07 mm (0.0012/0.0028 in.)
Top Compression Ring End Gap
CS4,CS6 .........................................................................................0.2/0.4 mm (0.008/0.016 in.)
CS8.5 (spec. 95xxxx)......................................................................0.25/0.4 mm (0.010/0.016 in.)
CS8.5 (spec. 92xxxx)......................................................................0.2/0.4 mm (0.008/0.016 in.)
CS10...............................................................................................0.2/0.4 mm (0.008/0.016 in.)
CS12...............................................................................................0.25/0.4 mm (0.010/0.016 in.)

1.15
Section 1
Safety and General Information
1
Middle Compression Ring End Gap
CS4,CS6 .........................................................................................0.2/0.4 mm (0.008/0.016 in.)
CS8.5 (spec. 95xxxx)......................................................................0.25/0.4 mm (0.010/0.016 in.)
CS8.5 (spec. 92xxxx)......................................................................0.2/0.4 mm (0.008/0.016 in.)
CS10...............................................................................................0.2/0.4 mm (0.008/0.016 in.)
CS12...............................................................................................0.25/0.4 mm (0.010/0.016 in.)
Oil Control Ring End Gap
CS4,CS6 .........................................................................................0.2/0.4 mm (0.0079/0.0157 in.)
CS8.5-12.........................................................................................0.2/0.7 mm (0.0079/0.028 in.)
Piston Thrust Face O.D.2
NewCS42.........................................................................................55.975/55.990 mm (2.2037/2.2043 in.)
CS62.........................................................................................65.975/65.990 mm (2.597/2.598 in.)
CS8.53(spec. 95xxxx) ..............................................................74.954/74.998 mm (2.9509/2.9527 in.)
CS8.53(spec. 92xxxx) ..............................................................77.954/77.998 mm (3.0691/3.0708 in.)
CS103.......................................................................................77.954/77.998 mm (3.0691/3.0708 in.)
CS123.......................................................................................84.954/84.998 mm (3.3446/3.3464 in.)
Max. Wear Limit
CS4 ..........................................................................................55.900 mm (2.20 in.)
CS6 ..........................................................................................65.900 mm (2.60 in.)
CS8.5 (spec. 95xxxx) ...............................................................74.898 mm (2.9487 in.)
CS8.5 (spec. 92xxxx) ...............................................................77.898 mm (3.0669 in.)
CS10 ........................................................................................77.898 mm (3.0669 in.)
CS12 ........................................................................................84.898 mm (3.3424 in.)
Piston Thrust Face-to-Cylinder Bore Running Clearance
CS4,CS62........................................................................................0.015/0.040 mm (0.0006/0.0016 in.)
CS8.5-123........................................................................................0.002/0.066 mm (0.0001/0.0026 in.)
Reduction System
Case Mounting Bolt(s) Torque
CS4,CS6 .........................................................................................10 N·m (88 in. lb.)
CS8.5-12.........................................................................................30 N·m (22 ft. lb.)
Crankshaft Gear Bolt Torque
CS4,CS6 .........................................................................................22 N·m (195 in. lb.)
CS8.5 (spec. 95xxxx)......................................................................22 N·m (195 in. lb.)
CS8.5 (spec. 92xxxx)......................................................................65 N·m (48 ft. lb.)
CS10-12..........................................................................................65 N·m (48 ft. lb.)
Retractable Starter
Mounting Screws to Blower Housing Torque
CS4,CS6 .........................................................................................6.5 N·m (57 in. lb.)
CS8.5-12.........................................................................................7 N·m (62 in. lb.)
RockerArm
Stud Into Cylinder Head Torque
CS4,CS6 .........................................................................................10 N·m (88 in. lb.)
Adjusting Jam Nut Torque .....................................................................7 N·m (62 in. lb.)

1.16
Section 1
Safety and General Information
Throttle Control
Throttle Control Lever Fastener Torque
CS4,CS6 .........................................................................................7-9 N·m (62-80 in. lb.)
CS8.5-12.........................................................................................9-11 N·m (80-97 in. lb.)
Valve Cover
Valve Cover Fastener Torque
CS4,CS6 .........................................................................................10 N·m (88 in. lb.)
CS8.5-12.........................................................................................11 N·m (97 in. lb.)
Valves and Valve Lifters
Intake Valve Stem-to-Valve Guide Running Clearance
CS4,CS6 .........................................................................................0.04/0.06 mm (0.0016/0.0024 in.)
CS8.5-12.........................................................................................0.037/0.064 mm (0.0015/0.0025 in.)
Exhaust Valve Stem-to-Valve Guide Running Clearance
CS4,CS6 .........................................................................................0.06/0.08 mm (0.002/0.003 in.)
CS8.5-12.........................................................................................0.045/0.072 mm (0.0018/0.0028 in.)
Intake Valve Guide I.D.
NewCS4,CS6...................................................................................5.5 mm (0.22 in.)
CS8.5-12 ..................................................................................6.0/6.012 mm (0.2362/0.2367 in.)
Max. Wear Limit
CS4,CS6...................................................................................5.60 mm (0.220 in.)
CS8.5-12 ..................................................................................6.10 mm (0.240 in.)
Exhaust Valve Guide I.D.
NewCS4,CS6...................................................................................5.5 mm (0.22 in.)
CS8.5-12 ..................................................................................6.0/6.012 mm (0.2362/0.2367 in.)
Max. Wear Limit
CS4,CS6...................................................................................5.6 mm (0.220 in.)
CS8.5-12 ..................................................................................6.0 mm (0.236 in.)
Valve Guide Reamer Size
STDCS4,CS6...................................................................................5.5 mm (0.216 in.)
CS8.5-12 ..................................................................................6.0 mm (0.236 in.)
Intake Valve Minimum Lift
CS4,CS6 .........................................................................................2.4 mm (0.094 in.)
CS8.5-12.........................................................................................2.7 mm (0.106 in.)
Exhaust Valve Minimum Lift
CS4,CS6 .........................................................................................2.7 mm (0.106 in.)
CS8.5-12.........................................................................................2.9 mm (0.114 in.)
Nominal Valve SeatAngle......................................................................45°
Valve-to-Tappet Clearance (Cold)..........................................................0.1 mm (0.004 in.)

1.17
Section 1
Safety and General Information
1
N·m = in. lb. x 0.113
N·m = ft. lb. x 1.356
in. lb. = N·m x 8.85
ft. lb. = N·m x 0.737
Torque
Conversions
Oil Drain Plugs Tightening Torque: N·m (in. lb.)
Size
M10x1.25
M12x1.50
IntoAluminum
17 (150)
20 (177)
Model
CS4, CS6
CS8.5, CS10, CS12
NOTES:
1. Values are in Metric units. Values in parenthesis are English equivalents. Lubricate threads with engine oil
prior to assembly.
2. Measure 5 mm (0.197 in.) above the bottom of the piston skirt at right angles to the piston pin.
3. Measure 10 mm (0.394 in.) above the bottom of the piston skirt at right angles to the piston pin.

1.18
Section 1
Safety and General Information