Kohler COMMAND CH18-745 User manual

SERVICE MANUAL
HORIZONTAL CRANKSHAFT
COMMAND CH18-745
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
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1.1
Section 1
Safety and General Information
1
Section 1
Safety and General Information
CH18-745
Safety Precautions
To ensure safe operation please read the following statements and understand their meaning.Also
refer to your equipment manufacturer'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 caution is ignored.
NOTE
Note is used to notify people of installation, operation, or maintenance information that is important
but not hazard-related.
For Your Safety!
These precautions should be followed at all times. Failure to follow these precautions could result in
injury to yourself and others.
Rotating Parts can cause severe
injury.
Stay away while engine is in
operation.
WARNING
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.
Hot Parts can cause severe burns.
Do not touch engine while operating
or just after stopping.
WARNING
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.
Accidental Starts can cause
severe injury or death.
Disconnect and ground spark plug
leads before servicing.
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.
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1.2
Section 1
Safety and General Information
Carbon Monoxide can cause
severe nausea, fainting or death.
Do not operate engine in closed or
confined area.
WARNING WARNING
Electrical Shock can cause injury.
Do not touch wires while engine is
running.
CAUTION
Uncoiling Spring can cause severe
injury.
Wear safety goggles or face
protection when servicing retractable
starter.
WARNING
Explosive Gas can cause fires and
severe acid burns.
Charge battery only in a well
ventilated area. Keep sources of
ignition away.
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.
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.
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.
Electrical Shock!
Never touch electrical wires or
components while the engine is
running. They can be sources of
electrical shock.
Explosive Fuel can cause fires and
severe burns.
Stop engine before filling fuel tank.
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.
Cleaning Solvents can cause
severe injury or death.
Use only in well ventilated areas
away from ignition sources.
WARNING
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.
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1.3
Section 1
Safety and General Information
1
A. Model No.
Version Code
S = Electric Start
C H 18 S
Engine Identification Numbers
When ordering parts, or in any communication
involving an engine, always give the Model,
Specification and Serial Numbers, including letter
suffixes if there are any.
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.
Figure 1-1. Engine Identification Decal Location.
Variation of
Basic Engine
B. Spec. No. 62500
Command Engine
Horizontal Crankshaft
Horsepower
17 = 17 HP
18 = 18 HP
20 = 20 HP
22 = 22 HP
23 = 23 HP
25 = 25 HP
26 = 26 HP
Numerical Designation
730
740
745
or
Engine Model Code
Code Model
62 CH18
64 CH20
66 CH22 (624 cc)
68 CH25
76 CH22/23 (674 cc)
78 CH26
CH730-0001
CH740-0001
CH745-0001
Complete Spec Number
(IncorporatingModel
No. with Variation No. of
Basic Spec.)
or
Figure 1-2. Explanation of Engine Identification Numbers.
C. Serial No.
Year Manufactured Code
Code Year
21 1991
22 1992
23 1993
24 1994
25 1995
26 1996
27 1997
28 1998
29 1999
Factory Code
3305810334
Code Year
30 2000
31 2001
32 2002
33 2003
34 2004
35 2005
Identification Decal
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1.4
Section 1
Safety and General Information
Oil Recommendations
Using the proper type and weight of oil in the crankcase
is extremely important. So is checking oil daily and
changing oil regularly. Failure to use the correct oil, or
usingdirty oil,causes prematureenginewear andfailure.
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 in the following table.
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explode if ignited. Before servicing the fuel system,
make sure there are no sparks, open flames or other
sources of ignition nearby as these can ignite gasoline
vapors. Disconnect and ground the spark plug leads to
prevent the possibility of sparks from the ignition
system.
General Recommendations
Purchase gasoline in small quantities and store in
clean, approved containers.A container 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 ensure 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.
Unleadedgasoline isrecommended asitleavesless
combustionchamber depositsandreduces harmful
exhaust emissions. Leaded gasoline is not
recommendedand must not beusedon EFIengines,
oron othermodels whereexhaust emissionsare
regulated.
Gasoline/Alcohol blends
Gasohol(upto 10%ethyl alcohol,90% unleaded
gasolineby volume)isapproved asafuel forKohler
engines.Other gasoline/alcoholblendsare not
approved.
Gasoline/Ether blends
MethylTertiaryButyl Ether(MTBE) andunleaded
gasoline blends (up to a maximum of 15% MTBE by
volume)are approvedasafuel forKohlerengines. Other
gasoline/etherblendsare notapproved.
NOTE: Using other than service class SG, SH, SJ or
higheroil orextendingoil changeintervals
longerthan recommendedcancause engine
damage.
NOTE: Synthetic oils meeting the listed classifications
may be used with oil changes performed at the
recommendedintervals.However,to allow
piston rings to properly seat, a new or rebuilt
engineshould beoperated foratleast50hours
usingstandard petroleumbasedoil before
switching to synthetic oil.
Alogo or symbol on oil containers identifies theAPI
service class and SAE viscosity grade. See Figure 1-3.
Figure 1-3. Oil Container Logo.
Referto Section6 -“Lubrication System”for detailed
procedures on checking the oil, changing the oil and
changing the oil filter.
*
*Use of synthetic oil having 5W-20 or 5W-30 rating is
acceptable, up to 40°F.
**Synthetic oils will provide better starting in extreme
cold (below -10°F).
**
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1.5
Section 1
Safety and General Information
1
Periodic 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
Theserequired maintenanceprocedures shouldbeperformed atthefrequency statedin thetable.They shouldalso
beincluded aspart ofany seasonaltune-up.
1Perform these maintenance procedures more frequently under extremely dusty, dirty conditions.
2Have a Kohler Engine Service Dealer perform this service.
3Cleanout Kits 25 755 20-S (black) or 25 755 21-S (gold) allow cooling areas to be cleaned without removing
shrouds.
Storage
Ifthe enginewill beout ofservice fortwo monthsor
more, use the following storage procedure.
1. Clean the exterior surfaces of the engine. On
Electronic Fuel Injected (EFI) engines, avoid
spraying water at the wiring harness or any of the
electrical components.
2. Change the oil and oil filter while the engine is still
warmfrom operation.See“Change OilandOil
Filter” in Section 6.
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 manufacturer’s
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 to 3 minutes to get stabilized fuel
into the rest of the system. Close the fuel shut-off
valve when the unit is being stored or transported.
To empty the system, run the engine until the tank
and the system are empty.
4. Remove the spark plugs and add one tablespoon
of engine oil into each spark plug hole. Install the
spark plugs, but do not connect the plug leads.
Crankthe enginetwoor threerevolutions.
5. On equipment with an EFI engine, disconnect the
battery or use a battery minder to keep the battery
chargedduringstorage.
6. Store the engine in a clean, dry place.
• Replace fuel filter1(EFI engines). Section 5B
Daily or Before
Starting Engine
Maintenance Required Refer to:Frequency • Fill fuel tank. Section 5
• Check oil level. Section 6
• Check air cleaner for dirty1, loose, or damaged parts. Section 4
• Check air intake and cooling areas, clean as necessary1. Section 4
• Service precleaner element1. Section 4
Every 25 Hours • Replace air cleaner element1. Section 4
• Change oil. (More frequently under severe conditions.) Section 6
• Remove cooling shrouds and clean cooling areas1,3. Section 4
• Check oil cooler fins, clean as necessary (if equipped). Section 6
• Check spark plug condition and gap. Section 8
• Change oil filter. Section 6
Annually or
Every 500 Hours • Have bendix starter drive serviced2. Section 8
• Have solenoid shift starter disassembled and cleaned2. Section 8
Every 100 Hours
Every 200 Hours
Every 1500 Hours • Have crankshaft spline lubricated2. Section 2
Every 500 Hours
Every 250 Hours • Replace heavy-duty air cleaner element and check inner element1. Section 4
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1.6
Section 1
Safety and General Information
Figure 1-4. Typical Engine Dimensions CH Series with Standard Flat Air Cleaner.
Dimensions in millimeters.
Inch equivalents shown in ().
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1.7
Section 1
Safety and General Information
1
Figure 1-5. Typical Engine Dimensions CH EFI Series with Heavy-Duty Air Cleaner.
Dimensions in millimeters.
Inch equivalents shown in ().
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1.8
Section 1
Safety and General Information
General Specifications¹
Power(@ 3600RPM, correctedto SAEJ1995)
CH18............................................................................................................................13.4 kW (18 HP)
CH20............................................................................................................................14.9 kW (20 HP)
CH22/23.......................................................................................................................16.4 kW (22 HP)
CH25, CH730...............................................................................................................18.4 kW (25 HP)
CH26............................................................................................................................19.4 kW (26 HP)
CH740..........................................................................................................................20.1 kW (27 HP)
CH745..........................................................................................................................20.9 kW (28 HP)
Peak Torque
CH18 - @ 2200 RPM ...................................................................................................44.4 N·m (32.8 ft. lb.)
CH20 - @ 2600 RPM ...................................................................................................44.2 N·m (32.6 ft. lb.)
CH22/23 - @ 2200 RPM ..............................................................................................51.7 N·m (38.2 ft. lb.)
CH25, CH730 - @ 2800 RPM ......................................................................................54.1 N·m (39.9 ft. lb.)
CH26 - @ 2800 RPM ...................................................................................................54.2 N·m (40.0 ft. lb.)
CH740 - @ 3000 RPM .................................................................................................57.9 N·m (42.7 ft. lb.)
CH745 - @ 2200 RPM .................................................................................................60.7 N·m (44.8 ft. lb.)
Bore
CH18, CH20, CH22 (624 cc)........................................................................................77 mm (3.03 in.)
CH22/23 (674 cc).........................................................................................................80 mm (3.15 in.)
CH25, CH26, CH730-745.............................................................................................83 mm (3.27 in.)
Stroke .................................................................................................................................67 mm (2.64 in.)
Displacement
CH18, CH20, CH22 (624 cc)........................................................................................624 cc (38 cu. in.)
CH22/23 (674 cc).........................................................................................................674 cc (41 cu. in.)
CH25, CH26, CH730-745.............................................................................................725 cc (44 cu. in.)
Compression Ratio
CH18, CH20, CH22/23.................................................................................................8.5:1
CH25, CH26, CH730-745.............................................................................................9.0:1
Dry Weight
CH18, CH20, CH22/23.................................................................................................41 kg (90 lb.)
CH25, CH26, CH730-745.............................................................................................43 kg (94 lb.)
Oil Capacity (with filter)
CH18, CH20, CH22/23, CH25, CH26, CH730-745 ......................................................1.9 L (2.0 U.S. qt.)
Angle of Operation - Maximum (At Full Oil Level)All Directions .........................................25°
Blower Housing and Sheet Metal
M5 Fasteners Torque..........................................................................................................4.0 N·m (35 in. lb.)
M6 Fasteners Torque..........................................................................................................6.8 N·m (60 in. lb.)
Rectifier-Regulator Fastener Torque ...................................................................................4.0 N·m (35 in. lb.)
¹Valuesarein Metricunits.Values inparentheses areEnglish equivalents. Lubricatethreads withengine oilprior
to assembly.
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1.9
Section 1
Safety and General Information
1
Camshaft
End Play (With Shim) .................................................................................. 0.076/0.127mm (0.0030/0.0050in.)
Running Clearance ...................................................................................... 0.025/0.063 mm (0.0010/0.0025 in.)
Bore I.D.
New....................................................................................................... 20.000/20.025 mm (0.7874/0.7884 in.)
Max. Wear Limit .................................................................................... 20.038 mm (0.7889 in.)
Camshaft Bearing Surface O.D.
New....................................................................................................... 19.962/19.975 mm (0.7859/0.7864 in.)
Max. Wear Limit .................................................................................... 19.959 mm (0.7858 in.)
Carburetor and Intake Manifold
Intake Manifold Mounting Fastener Torque
Torque in Two Stages ............................................................................ initially to 7.4 N·m (66 in. lb.)
finally to 9.9 N·m (88 in. lb.)
Carburetor Mounting Screw Torque M6 ....................................................... 6.2-7.3 N·m (55-65 in. lb.)
Adapter (for Heavy DutyAir Cleaner) Mounting Fastener Torque ................ 7.3 N·m (65 in. lb.)
Connecting Rod
Cap Fastener Torque (torque in increments)
8 mm straight shank.............................................................................. 22.7 N·m (200 in. lb.)
8 mm step-down ................................................................................... 14.7 N·m (130 in. lb.)
6 mm straight shank.............................................................................. 11.3 N·m (100 in. lb.)
Connecting Rod-to-Crankpin Running Clearance
New....................................................................................................... 0.030/0.055 mm (0.0012/0.0022 in.)
Max. Wear Limit .................................................................................... 0.070 mm (0.0028 in.)
Connecting Rod-to-Crankpin Side Clearance .............................................. 0.26/0.63 mm (0.0102/0.0248 in.)
Connecting Rod-to-Piston Pin Running Clearance ...................................... 0.015/0.028 mm (0.0006/0.0011 in.)
Piston Pin End I.D.
New....................................................................................................... 17.015/17.023 mm (0.6699/0.6702 in.)
Max. Wear Limit .................................................................................... 17.036 mm (0.6707 in.)
Crankcase
Governor Cross Shaft Bore I.D.
6 mm Shaft
New ................................................................................................... 6.025/6.050 mm (0.2372/0.2382 in.)
Max. Wear Limit................................................................................. 6.063 mm (0.2387 in.)
8 mm Shaft
New ................................................................................................... 8.025/8.075 mm (0.3159/0.3179 in.)
Max. Wear Limit................................................................................. 8.088 mm (0.3184 in.)
Breather Cover Fastener Torque ................................................................. 7.3 N·m (65 in. lb.)
OilDrain PlugTorque ................................................................................... 13.6 N·m (10 ft. lb.)
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1.10
Section 1
Safety and General Information
Closure Plate
ClosurePlate FastenerTorque .............................................................. 24.4 N·m (216 in. lb.)
Crankshaft
End Play (Free) .................................................................................... 0.070/0.590 mm (0.0028/0.0230 in.)
End Play (With Thrust Bearing Components) ....................................... 0.070/0.270 mm (0.0028/0.0100 in.)
Except CH25 Engines Below Serial No. 2403500008 .................... 0.050/0.750 mm (0.0020/0.0295 in.)
Crankshaft Bore (In Crankcase)
New................................................................................................ 40.965/41.003 mm (1.6128/1.6143 in.)
Max. Wear Limit ............................................................................. 41.016 mm (1.6148 in.)
CrankshafttoSleeveBearing(Crankcase)
RunningClearance- New................................................................ 0.03/0.09 mm(0.0012/0.0035in.)
CrankshaftBore (InClosurePlate) -New .............................................. 40.987/40.974mm (1.6136/1.6131in.)
Crankshaft Bore (In Closure Plate)-to-Crankshaft
Running Clearance - New .............................................................. 0.039/0.074 mm (0.0015/0.0029 in.)
Flywheel End Main Bearing Journal
O.D. - New ..................................................................................... 40.913/40.935 mm (1.6107/1.6116 in.)
O.D. - Max. Wear Limit .................................................................. 40.84 mm (1.608 in.)
Max. Taper ..................................................................................... 0.022 mm (0.0009 in.)
Max. Out-of-Round ........................................................................ 0.025 mm (0.0010 in.)
Closure Plate End Main Bearing Journal
O.D. - New ..................................................................................... 40.913/40.935 mm (1.6107/1.6116 in.)
O.D. - Max. Wear Limit .................................................................. 40.84 mm (1.608 in.)
Max. Taper ..................................................................................... 0.022 mm (0.0009 in.)
Max. Out-of-Round ........................................................................ 0.025 mm (0.0010 in.)
Connecting Rod Journal
O.D. - New ..................................................................................... 35.955/35.973 mm (1.4156/1.4163 in.)
O.D. - Max. Wear Limit .................................................................. 35.94 mm (1.415 in.)
Max. Taper ..................................................................................... 0.018 mm (0.0007 in.)
Max. Out-of-Round ........................................................................ 0.025 mm (0.0010 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.
New - CH18, CH20, CH22 (624 cc) ............................................... 77.000/77.025 mm (3.0315/3.0325 in.)
New - CH22/23 (674 cc)................................................................. 80.000/80.025 mm (3.1496/3.1506 in.)
New - CH25, CH26, CH730-745 .................................................... 82.988/83.013 mm (3.2672/3.2682 in.)
Max. Wear Limit - CH18, CH20, CH22 (624 cc)............................. 77.063 mm (3.0340 in.)
Max. Wear Limit - CH22/23 (674 cc).............................................. 80.065 mm (3.1522 in.)
Max. Wear Limit - CH25, CH26, CH730-745.................................. 83.051 mm (3.2697 in.)
Max. Out-of-Round ........................................................................ 0.12 mm (0.0047 in.)
Max. Taper ..................................................................................... 0.05 mm (0.0020 in.)
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1.11
Section 1
Safety and General Information
1
Cylinder Head
CylinderHeadFastenerTorque
Hex.Flange Nut-Torquein TwoStages.......................................... initially to 16.9 N·m (150 in. lb.)
finally to 33.9 N·m (300 in. lb.)
Head Bolt - Torque in Two Stages .................................................. initially to 22.6 N·m (200 in. lb.)
finally to 41.8 N·m (370 in. lb.)
Max. Out-of-Flatness............................................................................ 0.076 mm (0.003 in.)
Rocker Arm Screw Torque.................................................................... 11.3 N·m (100 in. lb.)
Fan/Flywheel
Fan Fastener Torque ............................................................................ 9.9 N·m (88 in. lb.)
Flywheel Retaining ScrewTorque......................................................... 66.4 N·m (49 ft. lb.)
Governor
Governor Cross Shaft-to-Crankcase Running Clearance
6 mm Shaft .................................................................................... 0.013/0.075 mm (0.0005/0.0030 in.)
8 mm Shaft .................................................................................... 0.025/0.126 mm (0.0009/0.0049 in.)
Governor Cross Shaft O.D.
6 mm Shaft
New ............................................................................................ 5.975/6.012 mm (0.2352/0.2367 in.)
Max. Wear Limit.......................................................................... 5.962 mm (0.2347 in.)
8 mm Shaft
New ............................................................................................ 7.949/8.000 mm (0.3129/.3149 in.)
Max. Wear Limit.......................................................................... 7.936 mm (0.3124 in.)
Governor Gear Shaft-to-Governor Gear Running Clearance ................ 0.015/0.140 mm (0.0006/0.0055 in.)
Governor Gear Shaft O.D.
New................................................................................................ 5.990/6.000 mm (0.2358/0.2362 in.)
Max. Wear Limit............................................................................. 5.977 mm (0.2353 in.)
Governor Lever Nut Torque .................................................................. 6.8 N·m (60 in. lb.)
Ignition
Spark Plug Type (Champion®or Equivalent)......................................... RC12YC or Platinum 3071
Spark Plug Gap .................................................................................... 0.76 mm (0.030 in.)
Spark Plug Torque ................................................................................ 24.4-29.8 N·m (18-22 ft. lb.)
Ignition ModuleAir Gap ........................................................................ 0.28/0.33 mm (0.011/0.013 in.)
Ignition Module Fastener Torque .......................................................... 4.0-6.2 N·m (35-55 in. lb.)
Speed Sensor Air Gap (EFI engines).................................................... 1.250/1.750 mm (0.049/0.068 in.)
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1.12
Section 1
Safety and General Information
²Measure 6 mm (0.236 in.) above the bottom of the piston skirt at right angles to the piston pin.
Muffler
MufflerRetainingNutTorque.................................................................. 24.4 N·m (216 in. lb.)
Oil Filter
Oil Filter Torque .................................................................................... 10.4-12.7 N·m (90-110 in. lb.)
Oil Cooler
Oil Cooler/Adapter Nipple Torque ......................................................... 27 N·m (20 ft. lb.)
Piston, Piston Rings, and Piston Pin
Piston-to-Piston Pin Running Clearance............................................... 0.006/0.017 mm (0.0002/0.0007 in.)
Piston Pin Bore I.D.
New................................................................................................ 17.006/17.012 mm (0.6695/0.6698 in.)
Max. Wear Limit ............................................................................. 17.025 mm (0.6703 in.)
Piston Pin O.D.
New................................................................................................ 16.995/17.000 mm (0.6691/0.6693 in.)
Max. Wear Limit ............................................................................. 16.994 mm (0.6691 in.)
Top Compression Ring-to-Groove Side Clearance
CH18, CH20, CH22 (624 cc).......................................................... 0.040/0.080 mm (0.0016/0.0031 in.)
CH22/23 (674 cc)........................................................................... 0.030/0.076 mm (0.0012/0.0030 in.)
CH25, CH26, CH730-745............................................................... 0.025/0.048 mm (0.0010/0.0019 in.)
Middle Compression Ring-to-Groove Side Clearance
CH18, CH20, CH22 (624 cc).......................................................... 0.040/0.080 mm (0.0016/0.0031 in.)
CH22/23 (674 cc)........................................................................... 0.030/0.076 mm (0.0012/0.0030 in.)
CH25, CH26, CH730-745............................................................... 0.015/0.037 mm (0.0006/0.0015 in.)
Oil Control Ring-to-Groove Side Clearance
CH18, CH20, CH22 (624 cc).......................................................... 0.060/0.202 mm (0.0024/0.0080 in.)
CH22/23 (674 cc)........................................................................... 0.046/0.196 mm (0.0018/0.0077 in.)
CH25, CH26, CH730-745............................................................... 0.026/0.176 mm (0.0010/0.0070 in.)
Top and Center Compression Ring End Gap
New Bore - CH18, CH20, CH22 (624 cc) ....................................... 0.25/0.45 mm (0.0098/0.0177 in.)
New Bore - CH22 (674 cc) ............................................................. 0.18/0.46 mm (0.0071/0.0181 in.)
New Bore - CH25, CH26, CH730-745............................................ 0.25/0.56 mm (0.0100/0.0224 in.)
Used Bore (Max.) - CH18, CH20, CH22 (624 cc)........................... 0.77 mm (0.030 in.)
Used Bore (Max.) - CH22/23 (674 cc)............................................ 0.80 mm (0.0315 in.)
Used Bore (Max.) - CH25, CH26, CH730-745 ............................... 0.94 mm (0.037 in.)
Piston Thrust Face O.D.²
New - CH18, CH20, CH22 (624 cc) ............................................... 76.967/76.985 mm (3.0302/3.0309 in.)
New - CH22/23 (674 cc)................................................................. 79.963/79.979 mm (3.1481/3.1488 in.)
New - CH25, CH26, CH730-745 .................................................... 82.986 mm (3.3194 in.)
Max. Wear Limit - CH18, CH20, CH22 (624 cc)............................. 76.840 mm (3.0252 in.)
Max. Wear Limit - CH22 (674 cc)................................................... 79.831 mm (3.1430 in.)
Max. Wear Limit - CH25, CH26, CH730-745.................................. 82.841 mm (3.3136 in.)
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

1.13
Section 1
Safety and General Information
1
Piston, Piston Rings, and Piston Pin cont.
PistonThrust Face-to-CylinderBore²RunningClearance
New - CH18, CH20, CH22 (624 cc) ............................................... 0.014/0.057 mm (0.0005/0.0022 in.)
New - CH22/23 (674 cc)................................................................. 0.021/0.062 mm (0.0008/0.0024 in.)
New - CH25, CH26, CH730-745 .................................................... 0.001/0.045 mm (0.039/0.0018 in.)
Speed Control Bracket
Fastener Torque ................................................................................... 7.3-10.7 N·m (65-95 in. lb.)
Starter Assembly
Thru Bolt Torque
UTE/Johnson Electric, Eaton (Inertia Drive) ................................... 4.5-5.7 N·m (40-50 in. lb.)
Nippondenso (Solenoid Shift)......................................................... 4.5-7.5 N·m (40-84 in. lb.)
Delco-Remy (Solenoid Shift) .......................................................... 5.6-9.0 N·m (49-79 in. lb.)
Mounting Screw Torque (All)................................................................. 15.3 N·m (135 in. lb.)
Brush Holder Mounting Screw Torque
Delco-Remy Starter........................................................................ 2.5-3.3 N·m (22-29 in. lb.)
Solenoid (Starter)
Mounting Hardware Torque
NippondensoStarter .......................................................................6.0-9.0 N·m (53-79 in. lb.)
Delco-Remy Starter.........................................................................4.0-6.0 N·m (35-53 in. lb.)
Nut, Positive (+) Brush Lead Torque
NippondensoStarter .......................................................................8.0-12.0 N·m (71-106 in. lb.)
Delco-Remy Starter.........................................................................8.0-11.0 N·m (71-97 in. lb.)
Stator
Mounting Screw Torque ........................................................................ 6.2 N·m (55 in. lb.)
Throttle/Choke Controls
Governor Control Lever Fastener Torque ............................................. 9.9 N·m (88 in. lb.)
Valve Cover
Valve Cover Fastener Torque
Gasket Style Cover ........................................................................ 3.4 N·m (30 in. lb.)
Black O-Ring Style Cover
w/Shoulder Screws.................................................................... 5.6 N·m (50 in. lb.)
w/Flange Screws and Spacers .................................................. 9.9 N·m (88 in. lb.)
Brown O-Ring Style Cover w/Integral Metal Spacers...................... 9.9 N·m (88 in. lb.)
Valves and Valve Lifters
Hydraulic Valve Lifter to Crankcase Running Clearance........................0.0241/0.0501 mm (0.0009/0.0020 in.)
Intake Valve Stem-to-Valve Guide Running Clearance ......................... 0.038/0.076 mm (0.0015/0.0030 in.)
Exhaust Valve Stem-to-Valve Guide Running Clearance ...................... 0.050/0.088 mm (0.0020/0.0035 in.)
Intake Valve Guide I.D.
New ................................................................................................ 7.038/7.058 mm(0.2771/0.2779in.)
Max. Wear Limit............................................................................. 7.135 mm (0.2809 in.)
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

1.14
Section 1
Safety and General Information
Valves and Valve Lifters cont.
Exhaust Valve Guide I.D.
New................................................................................................ 7.038/7.058 mm (0.2771/0.2779 in.)
Max. Wear Limit ............................................................................. 7.159 mm (0.2819 in.)
Valve Guide Reamer Size
Standard......................................................................................... 7.048 mm (0.2775 in.)
0.25 mm O.S.................................................................................. 7.298 mm (0.2873 in.)
Intake Valve Minimum Lift..................................................................... 8.07 mm (0.3177 in.)
Exhaust Valve Minimum Lift.................................................................. 8.07 mm (0.3177 in.)
NominalValveSeatAngle ..................................................................... 45°
General Torque Values
Metric Fastener Torque Recommendations for Standard Applications
Tightening Torque: N·m (in. lb.) + or - 10%
Property Class Noncritical
Fasteners
IntoAluminum
Size
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%
Property Class Noncritical
Fasteners
IntoAluminum
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 (55) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)
5.8 8.8 10.9 12.9
4.8 5.8 10.9 12.9
4.8
8.8
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

1.15
Section 1
Safety and General Information
1
English Fastener Torque Recommendations for Standard Applications
Grade 2 or 5
Fasteners Into
Aluminum
Size
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) --------- --------- ---------
Size
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) 142.4 (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) ---------
5/8-11 149.2 (110) 244.1 (180) 352.6 (260) ---------
5/8-18 189.8 (140) 311.9 (230) 447.5 (330) ---------
3/4-10 199.3 (150) 332.2 (245) 474.6 (350) ---------
3/4-16 271.2 (200) 440.7 (325) 637.3 (470) ---------
Tightening Torque: N·m (ft. lb.) + or - 20%
Tightening Torque: N·m (in. lb.) + or - 20%
Grade 2 Grade 5 Grade 8
Bolts, Screws, Nuts and Fasteners
Assembled Into Cast Iron or Steel
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
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

1.16
Section 1
Safety and General Information
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

2.1
Section 2
Special Tools
2
Section 2
Special Tools
CH18-745
Certain quality tools are designed to help you perform specific disassembly, repair, and reassembly procedures.
By using tools designed for the job, you can service engines easier, faster, and safer! In addition, you’ll increase
your service capabilities and customer satisfaction by decreasing engine downtime.
Kohler special tools are handled by SPX Corp., a division of Owatonna Tool Corp. (OTC). The tools are easy to
purchase by contacting SPX/OTC by phone, fax, or mail.
Phone: [phone]
International:1-507-455-7223
8:00 am – 8:00 pm EST
Fax: [phone]
1-586-578-7375
International:1-507-455-7063
Mail: SPX Corp., OTC
28635 Mound Rd.
Warren, MI 48092-3499
Some special tools for this engine are:
Camshaft Endplay Plate........................................................................................ KO1031
Flywheel Strap Wrench ......................................................................................... NU10357
Flywheel Puller Kit................................................................................................. NU3226
Rocker Arm Spanner Wrench................................................................................ OEM6200
Valve Guide Reamer ............................................................................................. KO1026
Water Manometer ................................................................................................. KO1048
Cylinder Leakdown Tester ..................................................................................... KO3219
Ignition System Tester ........................................................................................... KO1046
Hydraulic Lifter Removal/Reinstallation Tool.......................................................... KO1044
Starter Service Kit ................................................................................................. KO3226
Starter Retaining Ring Tool.................................................................................... 25 761 18-S
Vacuum Gauge ..................................................................................................... KO3223
Tachometer (Digital Inductive)............................................................................... KO3216
SparkAdvanceModule (SAM)Tester ..................................................................... KO3222
Rectifier-RegulatorTester ....................................................................................... KO3221
Electronic Fuel Injection (EFI) Service Tools
EFI Service Kit ...................................................................................................... KO3217
GaugeAssembly ............................................................................................... KO3217-4
Pliers................................................................................................................. KO3217-5
Circuit Tester ..................................................................................................... KO3217-6
Jumper Plug, Red (for metal cased ECU) ......................................................... KO3217-7
Tee Valve Assembly .......................................................................................... KO3217-8
Jumper Plug, Blue (for plastic cased ECU) ....................................................... KO3217-9
Some of the specialty tools are shown and mentioned at various points in this manual.Acomplete catalog of
availabletools maybe orderedunderKohler PartNo. TP-2546.The toolpricelist isavailable underKohlerPart No.
TP-2547.
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com

2.2
Section 2
Special Tools
Figure 2-1. Tool Catalog and Price List.
Special Tools You Can Make
Flywheel Holding Tool
Flywheel removal and reinstallation becomes a “snap”
using a handy holding tool which can be made out of an
old“junk” flywheelring gearas showninFigure 2-2.
Using an abrasive cut-off wheel, cut out a six tooth
segmentof thering gearas shown.Grind offanyburrs
or sharp edges. The segment can be used in place of a
strapwrench. Invertthe segmentandplace itbetween
the ignition bosses on the crankcase so that the tool
teethengage theflywheel ringgearteeth. Thebosses
will “lock” the tool and flywheel in position for loosening,
tighteningor removingwitha puller.
Figure 2-2. Flywheel Holding Tool.
RockerArm/Crankshaft Tool
If you don’t have a spanner wrench to lift the rocker
arms or turn the crankshaft, you can make a tool for
doing this out of an old junk connecting rod.
Figure 2-3. Rocker Arm/Crankshaft Tool.
Cylinder Leakdown Tester
ACylinder Leakdown Tester (SPX Part No. KO3219
formerlyKohler 25761 05-S)isavaluablealternate toa
compression test on these engines. See Figure 2-4. By
pressurizingthe combustionchamber fromanexternal
airsource, thistool candetermine ifvalves orrings are
leaking. Instructions for using this tester are found in
Section 3 of this manual.
Find a used connecting rod from a 10 HP or larger
engine. Remove and discard the rod cap. If it is a Posi-
Lock rod, you will also need to remove the studs. If it is
a Command rod, you will need to grind off the aligning
steps, so the joint surface is flat. Find a 1 in. long
capscrew with the correct thread size to match the
threads in the connecting rod. Obtain a flat washer
with the correct I.D. to slip on the capscrew and an
O.D. of approximately 1 in. Kohler Part No. 12 468 05-S
can be used if you don’t have the right size on hand.
Assemble the capscrew and washer to the joint
surface of the rod, as shown in Figure 2-3.
Figure 2-4. Cylinder Leakdown Tester.
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
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2.3
Section 2
Special Tools
2
Figure 2-5. Loctite®5900Aerosol Dispenser.
Camshaft Break-in Lubricant
Camshaftlubricant, KohlerPart No.25 357 14-S
(ValsparZZ613),shouldbe usedwheneveranew
camshaft and lifters are installed for proper break-in
upon initial startup. Lubricant is included with each
replacement camshaft and lifter, or may also be
obtained separately in a 1/8 oz handy dispensing tube
by the part number listed. See Figure 2-6.
RTV Silicone Sealant
RTV silicone sealant is used as a gasket between the
crankcase and closure plate.
Only oxime-based, oil resistant RTV sealants, such as
those listed below, are approved for use. Loctite®Nos.
5900 and 5910 are recommended for best sealing
characteristics.
Loctite®Ultra Blue 587
Loctite®Ultra Copper
Loctite®Ultra Black 598
Loctite®5900 (Heavy Body)
Loctite®5910
NOTE: Always use fresh sealant. Using outdated
sealant can result in leakage.
Loctite®5900 is available in a 4 oz aerosol dispenser
with replacement tips under Kohler Part No.
25 597 07-S. See Figure 2-5.
Figure 2-6. Camshaft Break-in Lubricant.
Spline Drive Lubricant
Specialspline drivecrankshaftlubricant KohlerPartNo.
25 357 12-S is available in a 2.8 oz tube for use on all
splinedrive applications.Thislubricantprovides proper
protectionagainst wear-relateddamage.SeeFigure
2-7.
Figure 2-7. Crankshaft Spline Drive Lubricant.
Dielectric Grease
Dielectric grease is applied to the outside of the
terminalconnections onthe SMART-SPARK™ignition
modulesto preventformationof amoisture pathand
arcing between the terminals. The chart below lists the
approveddielectricgreases.
Dielectric Grease
Vendor
G.E./Novaguard
Fel-Pro
Vendor No./
Description Kohler
Part No.
25357 11-S
---
G661
Lubri-Sel
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
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