Kohler HYDRO 12.75, CS4, CS8.5, CS10, CS12 User Manual

...

COMMAND PRO CS

4-12.75 HP

HORIZONTAL CRANKSHAFT

SERVICE MANUAL

Section 1. Safety and General Information .............................................................................

Section 2. T ools & Aids ............................................................................................................

Section 3. T roubleshooting .....................................................................................................

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...........................................................................................................

Section 1

Safety and General Information

Safety Precautions

To ensure 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 caution is ignored.

NOTE

Note is used to notify people of installation, operation, or maintenance information that is important but not hazard-related.

Section 1

For Y our Safety!

These precautions should be followed at all times. Failure to follow these precautions could result in injury to yourself and others.

WARNING

Accidental Starts can cause severe injury or death.

Disconnect and ground spark plug lead before servicing.

Accidental St arts!

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.

WARNING

Rotating Parts can cause severe injury.

Stay away while engine is in operation.

Rotating Part s!

Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate the engine with covers, shrouds, or guards removed.

WARNING

Hot Parts can cause severe burns.

Do not touch engine while operating or just after stopping.

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.

1.1

Section 1 Safety and General Information

WARNING

Explosive Fuel can cause fires and severe burns.

Do not fill the fuel tank while the engine is hot or running.

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.

WARNING

Carbon Monoxide can cause severe nausea, fainting or death.

Avoid inhaling exhaust fumes, and never run the engine in a closed building or confined area.

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.

WARNING

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.

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.

Cleaning Solvents can cause severe injury or death.

Use only in well ventilated areas away from ignition sources.

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 T ension!

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.

CAUTION

Electrical Shock can cause injury.

Do not touch wires while engine is running.

Electrical Shock!

Never touch electrical wires or components while the engine is running. They can be sources of electrical shock.

1.2

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. A suffix letter designates a specific version as follows:

Section 1

Safety and General Information

Identification Decal

Figure 1-1. Engine Identification Decal Location.

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

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

C. Serial No.

Year Manufactured Code

Code Year

28 1998 29 1999 30 2000 31 2001 32 2002

C S 6 ST

911509

28 23701265

Code Year

33 2003 34 2004 35 2005 36 2006 37 2007

Suffix Designates

T Retractable S tart

S Electric S tart G Tapered Crankshaft P Threaded Crankshaft R Gear Reduction (2:1 or 6:1)

IMPORTANT ENGINE INFORMATION THIS ENGINE MEETS U.S. EPA PHASE II, 2002-

2005 CALIFORNIA AND EC STAGE II (SN:4)

Variation of Basic Engine

EMISSION CONTROL REGS FOR SI SMALL OFF– ROAD ENGINES

FAMILY TYPE APP

MODEL NO. CS6ST SPEC. NO. 911509 DISPL. (CC) SERIAL NO. 2823701265 OEM PROD. NO.

EMISSION COMPLIANCE PERIOD: EPA: CATEGORY A

Factory Code

CERTIFIED ON: UNLEADED GASOLINE

REFER TO OWNER'S MANUAL FOR SAFETY, MAINTENANCE SPECS, AND ADJUSTMENTS

1-800-544-2444 www.kohlerengines.com

KOHLER CO. KOHLER, WISCONSIN USA

(REF:_______________ )

A B

N432

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.

1.3

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.

Synthetic oils should not be used.

Figure 1-3. Viscosity Grades Table.

Fuel Recommendations

WARNING: Explosive Fuel!

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 insure easy starting.

Do not add oil to the gasoline.

Do not overfill the fuel tank. Leave room for the fuel to expand.

NOTE: Using other than service class SG, SH, SJ or

higher oil or extending oil change intervals longer than recommended can cause engine damage.

A logo or symbol on oil containers identifies the API service class and SAE viscosity grade. See Figure 1-4.

Figure 1-4. Oil Container Logo.

Refer to Section 6 - ‘‘Lubrication System’’ for detailed oil check and oil change procedures.

Fuel T yp e

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.

1.4

Maintenance Instructions

Section 1

Safety and General Information

WARNING: Accident al 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

Every 25 Hours

Every 50 Hours

Every 100 Hours

Maintenance RequiredFrequency

• Fill fuel tank.

• Check oil level.

• Check air cleaner for dirty, loose, or damaged parts.

• Check air intake and cooling areas, clean as necessary.

• Service precleaner element. Replace if necessary.

• Service solid foam element. Replace if necessary.

• Change oil.

• Replace air cleaner element.

• Remove cooling shrouds and clean cooling areas.

• Check all fittings and fasteners.

• Clean fuel shut-off valve filter. Replace if necessary.

Refer to:

Section 5 Section 6 Section 4 Section 4

Section 4

Section 4 Section 6

Section 4 Section 4 Section 1 Section 5

• Check muffler screen/spark arrestor. Clean/replace if necessary. Section 8

Section 11 Section 5 Section 7

Annually or

Every 300 Hours

• Check spark plug condition and gap. Replace if necessary.

• Check and adjust valve clearance when engine is cold.

• Check and adjust idle speed.

• Service starter motor drive, if so equipped.

• Have combustion chamber decarbonized.

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.

1.5

Section 1 Safety and General Information

347.00 (13.661)

373.00 (14.685)

66.00 (2.598)

162.00 (6.378)

321.50 (Straight PTO) (12.657)

143.00 (5.630)

100.00 (3.937)

162.00 (6.378)

30.00 (1.181)

106.00 (4.173)

5/16-24 [qty. 5] 14 mm (.551) deep

384.25 (15.128)

Spark Plug

Oil Fill

Oil Drain Plug

Mounting Face

5.00 (.197)

44.50 (1.752)

37.00 (1.457)

9.0 (.354) dia. [qty. 2]

9.0x14.0 (.354x.551) slot [qty.2]

80.00 (3.150)

Figure 1-5. T ypical Engine Dimensions CS4 and CS6.

145.25 (5.719)

380.03 (14.962)

Dimensions in millimeters. Inch equivalents shown in ( ).

1.6

452.90 (17.831)

Section 1

Safety and General Information

454.00 (17.874)

445.85

156.68 (6.168)

45°

30°

(17.553)

45°

30°

423.50 (16.673)

70.00 (2.756)

Spark Plug

Oil Fill

417.50 (Straight PTO) (16.437)

187.50 (7.382)

118.34 (4.659)

99.00 (3.898)

205.00 (8.071)

133.50 (5.256)

5/16-24 [qty. 4] 18 mm (.709) deep

3/8-16 [qty. 4] 18 mm (.709) deep

127.00 (5.000) dia.

110.00 (4.331) dia.

90.50 (3.563)

195.50 (7.697)

152.00 (5.984)

165.10 (6.500) dia.

5/16-24 [qty. 2] 18 mm (.709) deep

146.08 (5.751) dia.

103.00 (4.055)

298.00 (11.732)

Oil Drain Plug

Mounting Face

16.00 (.630)

37.00 (1.457)

62.00 (2.441)

102.00 (4.016)

11.00 (.433) dia. [qty. 2]

11.00x27 (.433x1.063) slot [qty. 2]

65.00 (2.559)

Dimensions in millimeters. Inch equivalents shown in ( ).

Figure 1-6. T ypical Engine Dimensions CS8.5 (spec. 92xxxx), CS10, and CS12 - 12.75.

1.7

Section 1 Safety and General Information

431.00

156.00 (6.142)

165.1 (6.50)

(16.968)

110 (4.33)

410.00 (16.142)

428.00 (16.850)

3/8-16 18 mm (.709) deep [qty. 4]

183.00 (7.205)

94.5

(3.720)

133.50 (5.256)

380.00 (14.961)

146.08 (5.78)

90.50

(3.563)

195.50 (7.697)

103.00

(4.055)

424.00 (16.693)

70.00 (2.756)

5/16-24 18 mm (.709) deep [qty. 2]

5/16-24 18 mm (.709) deep [qty. 4]

11.00x27.00

(.433x1.063)

slotted hole

[qty. 2]

16.00 (.630)

37.00 (1.457)

57.50 (2.264)

96.00

(3.780)

11 (.433) hole [qty. 2]

59.00 (2.323)

Figure 1-7. T ypical Engine Dimensions CS8.5 (spec. 95xxxx).

1.8

Dimensions in millimeters. Inch equivalents shown in ( ).

Safety and General Information

General Specifications

Power (@ 3600 RPM, exceeds SAE J1940 HP Standards)

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)

Hydro 12.75 .............................................................................................. 9.5 kW (12.75 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 (spec. 9415xx @ 2000 RPM) ........................................................... 22.6 N·m (16.7 ft. lb.)

CS12 (spec. 9416xx @ 2400 RPM) ........................................................... 24.9 N·m (18.4 ft. lb.)

Hydro 12.75 (@ 2400 RPM) ..................................................................... 30.6 N·m (22.6 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.)

Section 1

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.)

1.9

Section 1 Safety and General Information

General Specifications cont.

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

End Play ........................................................................................................... 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.)

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.)

1.10

Section 1

Safety and General Information

Connecting Rod cont.

Connecting Rod-to-Piston Pin Running Clearance.................................... 0.006/0.025 mm (0.0002/0.0001 in.)

Piston Pin End I.D.

New

CS4,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.

New

CS4,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.)

Flywheel End Main Bearing Journal O.D.

New

CS4,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.)

1.11

Section 1 Safety and General Information

Crankshaft cont.

PTO End Main Bearing Journal O.D.

New

CS4,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.

New

CS4,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.)

Cylinder Bore

Cylinder Bore I.D.

New

CS4 ...................................................................................................... 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.)

1.12

Safety and General Information

Electric Starter cont.

Mounting Bolts (To Block) Torque

CS8.5-12..................................................................................................... 16 N·m (141 in. lb.)

Flywheel

Flywheel Retaining Screw Torque

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)

Spark Plug Gap ............................................................................................... 0.76 mm (0.030 in.)

Section 1

Spark Plug Torque .......................................................................................... 20 N·m (14.7 ft. lb./177 in. lb.)

Ignition Module Air Gap ............................................................................... 0.4/0.6 mm (0.015/0.023 in.)

Ignition Module Mounting Screws Torque ................................................. 10 N·m (88 in. lb.)

Stator Mounting Screw Torque ..................................................................... 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.)

Oil Sentry™Indicator Light Retaining Nut Torque .................................... 0.6-0.8 N·m (5-7 in. lb.)

Piston, Piston Rings, and Piston Pin

Piston-to-Piston Pin Clearance

Piston Pin Bore I.D.

™

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.)

New

CS4,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.)

1.13

Section 1 Safety and General Information

Piston, Piston Rings, and Piston Pin cont.

Piston Pin O.D.

New

CS4,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.)

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.

New

CS42..................................................................................................... 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.)

1.14

Safety and General Information

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 St arter

Mounting Screws to Blower Housing Torque

CS4,CS6 ..................................................................................................... 6.5 N·m (57 in. lb.)

CS8.5-12..................................................................................................... 7 N·m (62 in. lb.)

Rocker Arm

Stud Into Cylinder Head Torque

CS4,CS6 ..................................................................................................... 10 N·m (88 in. lb.)

Adjusting Jam Nut Torque ............................................................................ 7 N·m (62 in. lb.)

Section 1

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.

New

CS4,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.

New

CS4,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.)

1.15

Section 1 Safety and General Information

Valves and Valve Lifters

Valve Guide Reamer Size

STD

CS4,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 Seat Angle ............................................................................. 45°

Valve-to-Tappet Clearance (Cold) ................................................................ 0.1 mm (0.004 in.)

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.

Oil Drain Plugs Tightening Torque: N·m (in. lb.)

Size M10x1.25 M12x1.50

Into Aluminum

17 (150) 20 (177)

Model

CS4, CS6

CS8.5, CS10, CS12

Torque

Conversions

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

1.16

Section 2

Tools & Aids

Section 2

Tools & Aids

Certain quality tools are designed to help you perform specific disassembly, repair, and reassembly procedures. By using tools designed for the job, you can properly service engines easier, faster, and safer! In addition, you’ll increase your service capabilities and customer satisfaction by decreasing engine downtime.

Here is the list of tools and their source.

Separate Tool Suppliers:

Kohler Tools Contact your source of supply.

SE Tools 415 Howard St. Lapeer, MI 48446 Phone 810-664-2981 Toll Free 800-664-2981 Fax 810-664-8181

Design Technology Inc. 768 Burr Oak Drive Westmont, IL 60559 Phone 630-920-1300

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Section 2 Tools & Aids

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Section 2

Tools & Aids

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2.3

Section 2 Tools & Aids

Special Tools You Can Make

Flywheel Holding T ool (Electric S tart Models Only)

A flywheel holding tool can be made out of an old junk flywheel ring gear as shown in Figure 2-1, and used in place of a strap wrench.

1. Using an abrasive cut-off wheel, cut out a six tooth segment of the ring gear as shown.

2. Grind off any burrs or sharp edges.

3. Invert the segment and place it between the ignition bosses on the crankcase so that the tool teeth engage the flywheel ring gear teeth. The bosses will lock the tool and flywheel in position for loosening, tightening or removing with a puller.

2. Remove the studs of a Posi-Lock rod or grind off the aligning steps of a Command rod, so the joint surface is flat.

3. Find a 1 in. long capscrew with the correct thread size to match the threads in the connecting rod.

4. Use a flat washer with the correct I.D. to slip on the capscrew and approximately 1” O.D. (Kohler Part No. 12 468 05-S). Assemble the capscrew and washer to the joint surface of the rod, as shown in Figure 2-2.

Figure 2-1. Flywheel Holding Tool.

Rocker Arm/Crankshaft Tool

A spanner wrench to lift the rocker arms or turn the crankshaft may be made out of an old junk connecting rod.

1. Find a used connecting rod from a 10 HP or larger engine. Remove and discard the rod cap.

Figure 2-2. Rocker Arm/Crankshaf t T ool.

2.4

Section 3

Troubleshooting

Section 3

Troubleshooting

Troubleshooting Guide

When troubles occur, be sure to check the simple causes which, at first, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank.

Some common causes of engine trouble are listed below. Use these to locate the causing factors.

Engine Cranks But Will Not Start

1. Empty fuel tank.

2. Fuel shut-off valve closed.

3. Key switch or kill switch in “off” position.

4. Low oil level.

5. Dirt or water in the fuel system.

6. Clogged fuel line.

7. Spark plug lead disconnected.

8. Faulty spark plug.

9. Faulty ignition module.

Engine Start s But Does Not Keep Running

1. Restricted fuel cap vent.

2. Dirt or water in the fuel system.

3. Faulty choke or throttle controls.

4. Loose wires or connections that short the kill terminal of ignition module to ground.

5. Faulty cylinder head gasket.

6. Faulty carburetor.

Engine Start s Hard

1. PTO drive is engaged.

2. Dirt or water in the fuel system.

3. Clogged fuel line.

4. Loose or faulty wires or connections.

5. Faulty choke or throttle controls.

6. Faulty spark plug.

7. Low compression.

8. Faulty ACR mechanism.

9. Weak spark/ignition.

Engine Will Not Crank

1. PTO drive is engaged.

2. Battery (if equipped) is discharged.

3. Safety interlock switch is engaged.

4. Loose or faulty wires or connections.

5. Faulty key switch or ignition switch.

6. Faulty electric starter or solenoid (electric start).

7. Pawls not engaging in drive cup (retractable start).

8. Seized internal engine components.

Engine Runs But Misses

1. Dirt or water in the fuel system.

2. Spark plug lead loose.

3. Loose wires or connections that intermittently short the kill terminal of ignition module to ground.

4. Engine overheated.

5. Faulty ignition module.

6. Faulty spark plug.

7. Carburetor malfunction.

Engine Will Not Idle

1. Restricted fuel cap vent.

2. Dirt or water in the fuel system.

3. Faulty spark plug.

4. Idle fuel adjusting needle improperly set.

5. Idle speed adjusting screw improperly set.

6. Low compression.

7. Stale fuel and/or gum in carburetor.

Engine Overheats

1. Air intake/grass screen, cooling fins, or cooling shrouds clogged.

2. Excessive engine load.

3. Low crankcase oil level.

4. High crankcase oil level.

5. Faulty carburetor.

Engine Knocks

1. Excessive engine load.

2. Low crankcase oil level.

3. Old/improper fuel.

4. Internal wear or damage.

3.1

Section 3 Troubleshooting

Engine Loses Power

1. Low crankcase oil level.

2. High crankcase oil level.

3. Dirty air cleaner element.

4. Dirt or water in the fuel system.

5. Excessive engine load.

6. Engine overheating.

7. Faulty spark plug.

8. Low compression.

9. Exhaust restriction.

Engine Uses Excessive Amount Of Oil

1. Incorrect oil viscosity/type.

2. Overfilled crankcase.

3. Clogged breather.

4. Worn or broken piston rings.

5. Worn cylinder bore.

6. Worn valve stems/valve guides.

Oil Leaks From Oil Seals, Gaskets

1. Crankcase breather is clogged or inoperative.

2. Loose or improperly torqued fasteners.

3. Piston blowby or leaky valves.

4. Restricted exhaust.

External Engine Inspection

Before cleaning or disassembling the engine, make a thorough inspection of its external appearance and condition. This inspection can give clues to what might be found inside the engine (and the cause) when it is disassembled.

• Check for buildup of dirt and debris on the crankcase, cooling fins, grass screen and other external surfaces. Dirt or debris on these areas are causes of overheating.

• Check for obvious fuel and oil leaks, and damaged components. Excessive oil leakage can indicate a clogged or improperly assembled breather, worn or damaged seals and gaskets, or loose or improperly torqued fasteners.

• Check the air cleaner cover and base for damage or indications of improper fit or sealing.

• Check the air cleaner element. Look for holes, tears, cracked or damaged sealing surfaces, or other damage that could allow unfiltered air into the engine. Also note if the element is dirty or clogged. These could indicate that the engine has had inadequate or infrequent maintenance.

• Check the carburetor throat for dirt. Dirt in the throat is further indication that the air cleaner was not functioning properly.

• Check the oil level. Note if the oil level is within the operating range on the dipstick, or if it is low or overfilled.

• Check the condition of the oil. Drain the oil into a container - the oil should flow freely. Dark, dirty, and/or thick oil could indicate infrequent maintenance or overheating. Check for metal chips and other foreign particles.

Sludge is a natural by-product of combustion; a small accumulation is normal. Excessive sludge formation could indicate the oil has not been changed at the recommended intervals, the incorrect type or weight of oil was used, overrich carburetion, or weak ignition, to name a few.

NOTE: It is good practice to drain oil at a

location away from the workbench. Be sure to allow ample time for complete drainage.

Cleaning the Engine

After inspecting the external condition of the engine, clean the engine thoroughly before disassembling it. Also clean individual components as the engine is disassembled. Only clean parts can be accurately inspected and gauged for wear or damage. There are many commercially available cleaners that will quickly remove grease, oil, and grime from engine parts. When such a cleaner is used, follow the

manufacturer’s instructions and safety precautions carefully.

Make sure all traces of the cleaner are removed before the engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil.

Basic Engine Tests

Crankcase Vacuum Test

A partial vacuum should be present in the crankcase when the engine is operating at normal temperatures. Pressure in the crankcase (normally caused by a clogged breather) can cause oil to be forced out at oil seals, gaskets, or other available spots.

Crankcase vacuum is best measured with water manometer or vacuum/pressure tester, see Section 2. Complete instructions are provided in the kits.

Test the crankcase vacuum, following the instructions, with the engine running at high idle speed (above 3500 RPM).

3.2

Section 3

Troubleshooting

1. The engine should have a minimum of 4 in. of vacuum. A vacuum less than 4 in. is usually due to internal wear or a bad gasket or seal allowing air to leak into the crankcase. A pressure is usually due to a problem with the breather.

Low/No Crankcase Vacuum or Pressure in Crankcase

Possible Cause

1. Crankcase breather clogged or inoperative.

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

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

4. Restricted exhaust.

Compression T est

A compression test or a cylinder leakdown test may be performed to check the condition of an engine. Insufficient compression pressure will result in a performance loss and may indicate leaking valves or damaged/worn piston rings.

2. Refer to the following chart for possible causes and solutions.

Solution

1. Disassemble breather, clean parts thoroughly, reassemble, and recheck pressure.

2. Replace all worn or damaged seals and gaskets. Make sure all fasteners are tightened securely. Use appropriate torque values and sequences when necessary.

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

4. Repair/replace restricted muffler/exhaust system.

Cylinder leakdown tester is a simple and inexpensive tester for small engines. The tester includes a quick disconnect for attaching the adapter hose and a holding tool.

Test the cylinder leakdown as follows:

Test the compression as follows:

1. Check/perform valve clearance adjustment.

2. Start engine if possible, and run for 3-5 minutes to warm it up, then stop.

3. Disconnect and ground spark plug lead. Remove the spark plug.

4. Install adapter and compression tester into spark plug hole.

5. Move the throttle control to the full/wide open position. Be sure the choke is off.

6. Crank engine over using recoil or electric starter and check results.

• Standard Compression Pressure:

400-600 kPa (57-85 psi) with ACR mechanism in operation.

Cylinder Leakdown T est

A cylinder leakdown test can be a valuable alternative to a compression test, especially on engines with ACR. By pressurizing the combustion chamber from an external air source you can determine if the valves or rings are leaking, and how badly.

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

2. Remove spark plug and air filter from engine.

3. Rotate crankshaft until piston (of cylinder being tested) is at top dead center (TDC) of the compression stroke. You will need to hold engine in this position while testing.

a. If the PTO end of the crankshaft is accessible,

the holding tool supplied with the tester can be used. Loosen the holding tool screws and expand the opening. Slide the tool onto the crankshaft as close as possible to the PTO face of the crankcase. If the slot in the tool can be aligned with one of the holes on the PTO face, find a bolt of appropriate length and thread size. Insert the bolt through the slot, and thread it into the selected hole, to prevent the tool from moving. Tighten the screws to lock the holding tool onto the crankshaft. If a PTO face hole is not accessible, tighten the screws to lock the holding tool onto the crankshaft. Insert the end of a 3/8" breaker bar into the slot, so the handle of the breaker bar is perpendicular to the crankshaft.

3.3

Section 3 Troubleshooting

b. If the flywheel end of the engine is more

accessible, you can use a breaker bar and socket on the flywheel nut/screw or a flywheel holding tool to hold it in position. When using these methods, you will need an assistant to hold it during the test.

c. If the engine is mounted in a piece of

equipment, you may be able to hold it by clamping or wedging a driven component. Just be certain the engine cannot rotate off of TDC in either direction.

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

5. Connect an adequate air source (70-100 psi) to the tester.

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

7. Connect tester quick-disconnect to the adapter. Note the gauge reading and listen for escaping air at the carburetor intake, exhaust outlet, and crankcase breather.

8. Check your test results against the table below:

Leakdown Test Results

Air escaping from crankcase breather ............................................... Defective rings or worn cylinder walls.

Air escaping from exhaust system ..................................................... Defective exhaust valve.

Air escaping from carburetor .............................................................. Defective intake valve.

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

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

present. Customer should start planning for overhaul or replacement.

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

Engine should be reconditioned or replaced.

3.4

Section 4

Air Cleaner and Air Intake System

Air Cleaners

General

These engines are equipped with one of three air cleaner configurations; the standard dual-element air cleaner assembly, an optional heavy-duty cyclonic air cleaner assembly, or a third design which uses an oiled, solid foam element. The first two styles have a replaceable, high-density paper element surrounded by an oiled-foam precleaner. See Figures 4-1 and 4-2. Servicing information for these two styles is on pages

4.1 through 4.4. The third design does not use a paper element, just the foam. See Figure 4-14. Servicing information for the third design is on page 4.5. The heavy-duty air cleaner assemblies also contain a lower swirl chamber which separates the dirt particles from the incoming air for extended service intervals.

Section 4

Air Intake and Air Cleaner System

Figure 4-2. Heavy-Duty, Cyclonic Air Cleaner.

Service

Check the air cleaner daily or before starting the engine. Check for buildup of dirt and debris, along

with loose or damaged components.

Figure 4-1. Standard Dual-Element Air Cleaner.

NOTE: Operating the engine with loose or damaged

air cleaner components could allow unfiltered air into the engine causing premature wear and failure.

Figure 4-3. Removing Cover Knob Standard.

4.1

Section 4 Air Cleaner and Air Intake System

To service the precleaner perform the following steps:

1. Remove the air cleaner cover knob (standard air cleaner) or unsnap the latches (heavy-duty air cleaner), and remove the cover/housing. See Figures 4-3 and 4-4.

2. Remove the precleaner from the filter element. If element is not secured to the air cleaner base with a wing nut, remove the filter element and precleaner from the cover/housing, as an assembly before separating. See Figures 4-5 and 4-6.

Figure 4-4. Unsnapping Heavy-Duty Latches.

Figure 4-5. Standard Element/Precleaner Assembly .

3. Wash the precleaner in warm water with detergent. Rinse the precleaner thoroughly until all traces of detergent are eliminated. Squeeze out excess water (do not wring). Allow the precleaner to air dry.

4. Saturate the precleaner with new engine oil. Squeeze out all excess oil.

5. Install the precleaner over the paper element. If the element was not secured with a wing nut (some heavy-duty air cleaners) install the element/precleaner assembly, small end first, into the cover/housing.

6. Reinstall the air cleaner cover/housing assembly. Secure with the knob or latches.

Figure 4-6. Heavy-Duty Element/Precleaner Assembly .

Precleaner Service

If so equipped, wash and reoil the precleaner every 25 hours of operation (more often under extremely dusty

or dirty conditions).

4.2

Figure 4-7. Removing Standard Precleaner.

Section 4

Air Intake and Air Cleaner System

Figure 4-8. Removing Heavy-Duty Precleaner.

Figure 4-9. Removing Heavy-Duty Lower Chamber.

Figure 4-11. Inst alling Heavy-Duty Cover/Housing.

Paper Element Service

Every 100 hours of operation (more often under extremely dusty or dirty conditions), check the paper element. Replace the element as necessary. Follow these steps:

1. Standard Air Cleaner:

Loosen the air cleaner cover knob and remove the cover. Remove the wing nut and lift off the air cleaner element with precleaner. Remove the precleaner from the paper element. Service the precleaner.

Heavy-Duty, Cyclonic Air Cleaner:

Unhook the latches and remove the housing assembly from the mounting base. Remove the wing nut (some models) securing air cleaner/ precleaner assembly, or pull the complete filter assembly out of the housing. Remove the precleaner from the paper element. Service the precleaner.

2. Do not wash the paper element or use pressurized air, as this will damage the element. Replace a dirty, bent, or damaged element with a genuine Kohler element. Handle new elements carefully; do not use if the sealing surfaces are bent or damaged.

Figure 4-10.

4.3

Section 4 Air Cleaner and Air Intake System

3. When servicing the air cleaner, check the air cleaner base, and cover/housing assembly. Make sure it is secure and not bent or damaged. On a heavy-duty air cleaner, unsnap the latches and clean out the lower swirl/dirt chamber. See Figure 4-9. Make sure the air slots in the upper section of the housing and in the lower chamber are open. See Figure 4-10. Clean and inspect all components for damage or improper fit. Replace any components which are bent or damaged. Reassemble the lower chamber (heavy duty air cleaners).

NOTE: Before the air cleaner is reassembled make

sure the rubber seal is in position on the stud (standard only). Also inspect the foam seal on the base of the filter element, do not use if the condition of either is questionable in any way. Replace it with a new part before reassembling.

4. Standard Air Cleaner: Install the serviced precleaner over the element. Position the element/precleaner assembly on the base and secure with the wing nut. Reinstall the air cleaner cover and tighten securely. See Figure 4-5.

Heavy-Duty Cyclonic Air Cleaner

Make sure the main housing, lower swirl/dirt chamber, mounting hardware and latches are not damaged, bent or broken; affecting the sealing ability and operation of air cleaner housing. Clean and check all components as well as the airflow passages.

Air Cleaner Base

Make sure the air cleaner base is secured tightly to carburetor and not cracked, bent or damaged, preventing a proper seal.

Breather T ube

Make sure the breather tube is in good condition and connected to the air cleaner base or adapter and the breather cover. Replace the tube if it is cracked or damaged.

Heavy-Duty Cyclonic Cleaner:

Place the precleaner over the element and install it as an assembly into the cover/housing. Insert the small end first, into the housing, so the larger end with the foam seal is out (visible). Secure with the wing nut (if used). Secure the cover/ housing with the latches. See Figure 4-11.

Air Cleaner Components

Whenever the air cleaner cover is removed, or the paper element or precleaner is serviced, check the following:

Standard Air Cleaner

Make sure the element cover is not bent, distorted or damaged. Make sure the wing nut and rubber sleeve seal on the base stud are in place and in good condition, ensuring the element is sealed against leakage. (Some models the seal is fixed).

If the air cleaner element has a foam seal on the bottom, make sure it is in good condition and not damaged. See Figure 4-12.

Figure 4-12. Foam Seal.

Figure 4-13. Cutaway View .

4.4

+ 123 hidden pages

Kohler HYDRO 12.75, CS4, CS8.5, CS10, CS12 User Manual

Contents

Section 1

Section 2

Section 3

Section 4