Kohler ECH650, ECH749, ECH680, ECH630, ECH740 User Manual

...

ECH630-ECH749

HORIZONTAL CRANKSHAFT

SERVICE MANUAL

Contents

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

Section 2. Tools & Aids .............................................................................................................

Section 3. Troubleshooting ......................................................................................................

Section 4. Air Cleaner and Air Intake System .........................................................................

Section 5. Electronic Fuel Injection (EFI) System ..................................................................

Section 6. Lubrication System .................................................................................................

Section 7. Electrical System and Components ......................................................................

Section 8. Disassembly.............................................................................................................

Section 9. Inspection and Reconditioning ..............................................................................

Section 10. Reassembly............................................................................................................

Safety and General Information

Section 1

Safety and General Information

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.

Section 1

NOTE

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

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(s) before servicing.

Hot Parts can cause severe burns.

Do not touch engine while operating or just a er stopping.

WARNING

Hot Parts!

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 (–) ba ery cable from ba ery.

Engine components can get extremely hot from operation. To prevent severe burns, do not touch these areas while the engine is running, or immediately a er it is turned oﬀ . Never operate the engine with heat shields or guards removed.

WARNING

Rotating Parts can cause severe injury.

Stay away while engine is in operation.

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.

Explosive Fuel!

Gasoline is extremely ﬂ ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or ﬂ ames. Do not ﬁ ll 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.

Explosive Fuel can cause ﬁ res and severe burns.

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

1.1

Section 1 Safety and General Information

WARNING

Carbon Monoxide can cause severe nausea, fainting or death.

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

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.

WARNING

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 ﬂ ammable. Keep sparks, ﬂ ames, 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.

WARNING

Explosive Fuel can cause ﬁ res and severe burns.

Fuel systems ALWAYS remains under HIGH PRESSURE.

Fuel Fire and Burns!

Wrap a shop towel completely around the fuel pump module connector. Press the release bu on(s) and slowly pull the connector away from the fuel pump module allowing the shop towel to absorb any residual fuel in the high pressure fuel line. Any spilled fuel must be completely wiped up immediately.

Engine Identiﬁ cation Numbers

When ordering parts, or in any communication involving an engine, always give the Model, Speciﬁ cation and Serial Numbers, including le er suﬃ xes if there are any.

The engine identiﬁ cation numbers appear on a decal, or decals, aﬃ xed to the engine shrouding. See Figure 1-1. An explanation of these numbers is shown in Figure 1-2.

Identiﬁ cation

entiﬁ ca

Decal

ecal

WARNING

High Pressure Fluids can puncture skin and cause severe injury or death.

Do not work on fuel system without proper training or safety equipment.

High Pressure Fluid Puncture!

Fuel system is to be serviced only by properly trained personnel wearing protective safety equipment. Fluid puncture injuries are highly toxic and hazardous. If an injury occurs, seek immediate medical a ention.

1.2

Figure 1-1. Engine Identiﬁ cation Decal Location.

Model No.

Spec. No.

Electronic Fuel Injection (EFI)

Command Engine

Horizontal Crankshaft

Numerical Designation

630 650 680 730 740 749

ECH630-XXXX ECH650-XXXX ECH680-XXXX ECH730-XXXX ECH740-XXXX ECH749-XXXX

E C H 749

Section 1

Safety and General Information

Serial No.

Year Manufactured Code

Code Year

39 2009 40 2010 41 2011

Figure 1-2. Explanation of Engine Identiﬁ cation Numbers.

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 using dirty oil, causes premature engine wear and failure.

Oil Type

Use high-quality detergent oil of API (American Petroleum Institute) Service Class SJ or higher. Select

the viscosity based on the air temperature at the time of operation as shown in the following table.

39 05810334

Factory Code

Kohler 10W-30

10W-30

SAE 30

5W-30

°F -20 020324060

°C -30 -20 -10 0 10 20 30 40

50 80 100

1.3

Section 1 Safety and General Information

NOTE: Using other than service class SJ or higher oil

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

NOTE: Synthetic oils meeting the listed

classiﬁ cations may be used with oil changes performed at the recommended intervals. However, to allow piston rings to properly seat, a new or rebuilt engine should be operated for at least 50 hours using standard petroleum based oil before switching to synthetic oil.

A logo or symbol on oil containers identiﬁ es the API service class and SAE viscosity grade. See Figure 1-3.

Do not use gasoline le 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 overﬁ ll 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 (R+M)/2 or higher. In countries using the Research Octane Number (RON), it should be 90 octane minimum. Leaded gasoline is not recommended and must not be used on EFI engines or on other models where exhaust emissions are regulated.

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 including E20 and E85 are not to be used and not approved. Any failures resulting from use of these fuels will not be warranted.

Figure 1-3. Oil Container Logo.

Refer to Section 6 - Lubrication System for detailed procedures on checking the oil, changing the oil and changing the oil ﬁ lter.

Fuel Recommendations

WARNING

Explosive Fuel can cause ﬁ res and severe burns.

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

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.

Gasoline/Ether Blends

Methyl Tertiary Butyl Ether (MTBE) and unleaded gasoline blends (up to a maximum of 15% MTBE by volume) are approved as a fuel for Kohler engines. Other gasoline/ether blends are not approved.

Periodic Maintenance Instructions

WARNING

Accidental Starts can cause severe injury or death.

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

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 (–) ba ery cable from ba ery.

Maintenance Schedule

Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair establishment or individual; however, warranty repairs must be performed by a

Kohler authorized service center.

1.4

Section 1

Safety and General Information

Maintenance Required Frequency

• Check oil level. Section 6

Daily or Before

Starting Engine

• Fill fuel tank. Section 5

• Check air cleaner for dirty

, loose, or damaged parts. Section 4

• Check air intake and cooling areas, clean as necessary.1 Section 4

Every 25 Hours

• Clean or replace precleaner (if equipped) clean as necessary.

• Replace element1 (low-proﬁ le air cleaner models). Section 4

Every 100 Hours

• Remove and clean shrouds and cooling areas.1 Section 4

• Change oil. (More frequently under severe conditions). Section 6

• Check oil cooler ﬁ ns, clean as necessary (if equipped). Section 6

Weekly or Every

150 Hours

• Check ﬁ lter minder.

• Inspect air ﬁ lter paper element and inlet screen area.4 Section 4

Section 4

• Replace fuel ﬁ lter1. Section 5

Every 200 Hours

• Clean, set gap or replace spark plug, and set gap. Section 7

• Change oil ﬁ lter. Section 6

Every 300 Hours

Annually or

Every 500 Hours

¹Perform these maintenance procedures more frequently under extremely dusty, dirty conditions. ²Have a Kohler Engine Service Dealer perform this service.

Low-proﬁ le air cleaner.

Heavy-duty air cleaner.

• Replace heavy-duty air cleaner element and check inner element.1 Section 4

• Have starter serviced.2 Section 7

Refer to:

1,3

Section 4

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. On EFI engines, avoid spraying water at the wiring harness or any of the electrical components.

2. Change the oil and oil ﬁ lter while the engine is still warm from operation. See Change Oil and Oil 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. Crank the engine two or three revolutions.

5. Disconnect the negative (-) ba ery cable or use a ba ery minder trickle charger while the unit is in storage.

6. Store the engine in a clean, dry place.

1.5

Section 1 Safety and General Information

342.52

(13.485)

Primary Air Filter

Element Removal

130.00 (5.118)

Air Filter Cover

Assembly Removal

230.20 (9.063)

Safety Air Filter

Element Removal

19.22

(0.757)

Spark Plug

15.70

(0.618)

142.89 (5.626)

88.20

(3.473)

Mounting

Hole “A”

424.29

(16.704)

OIL DIPSTICK

92.10

(3.626)

OIL FILL LOCATION

(18.560)

52.40

(20.063)

471.44

277.30

(10.917)

Engine

184.20 (7.252)

304.72

(11.997)

210.40 (8.284)

135.00

(5.315) Air Filter Rain Cap Removal

17.53

(0.690)

Spark Plug

LIFT STRAP

2X OIL DRAIN PLUG

3/8 NPT (IN.)

Dimensions in millimeters. Inch equivalents shown in [ ].

432.61

(17.032)

89.00

(3.504)

MOUNTING

HOLE “A”

622.63

(24.513)

7/16-20 UNF 2B (IN.)

38.10 (1.500)

155.58 (6.125)

1/4 IN. SQ.

KEYWAY

28.56

Ø(1.125)

152.08 (5.987)

OIL FILTER

85.50

(3.366)

97.38

(3.834)

OIL FILTER

52.75

(2.077)

104.00 (4.094)

89.00

(3.504)

ENGINE MOUNTING

SURFACE

301.59

(11.874)

SOLENOID

SHIFT

STARTER

286.49

(11.279)

30˚

30˚ 30˚

45˚ 45˚

51.20

(2.016)

ENGINE

MOUNTING

SURFACE

LIFT

STRAP

OIL FILL LOCATION

3/8-16 UNC 2B (IN.)

17.0 (0.669)

Ø142.88 (5.625) B.C.

7/16-14 UNC 2B (IN.)

21.0 (0.827)

Ø196.85 (7.75) B.C.

30˚

Figure 1-4. Typical Engine Dimensions with Heavy-Duty Air Cleaner.

1.6

17.07

(0.672)

SPARK PLUG

60.00

(2.362)

AIR CLEANER

COVER REMOVAL

426.44

(16.789)

302.63

(11.915)

12.15

(0.478)

17.53

(0.690)

SPARK PLUG

Section 1

Safety and General Information

Dimensions in millimeters. Inch equivalents shown in [ ].

FUEL FILTER

CRANKSHAFT

15.70

(0.618) OIL FILTER REMOVAL

1/4 IN. SQ. KEYWAY

8550

(3.366)

KEYWAY

101.38 (3.992)

142.89 (5.626)

MOUNTING HOLE

“A”

OIL FILL

3.05

(0.120)

OIL FILL

92.10

(3.626)

184.20 (7.252)

ENGINE

370.05

(14.569)

30.00

(1.181)

SPARK PLUG

FUEL PUMP

MOUNTING

HOLES

463.36

(18.242)

12.19

(0.480)

OIL DRAIN PLUG 3/8 IN. NPT

50.00 (1.969) SPARK PLUG

89.00

(3.504)

51.00

(2.008)

32.00 (1.260) EXHAUST PORT #2

12.00 (0.472) EXHAUST PORT #1

MUFFLER MOUNTING

OIL DIPSTICK

67.50 (2.657)

BOSSES

432.61 (17.032)

ENGINE MOUNTING SURFACE

7/16-20 UNF 28 IN.

38.10 (1.500)

152.08 (5.987)

OIL FILTER

4.00 (0.157) PILOT

MOUNTING SURFACE

100.00 (3.937)

MOUNTING

HOLE “A”

52.75

(2.077)

OIL FILTER

51.00

(2.008)

89.00

(3.504)

12.19 (0.480)

OIL DRAIN PLUG 3/8 IN. NPT

ENGINE MTG SURFACE

50.00 (1.969) EXHAUST PORT #1

(11.164)

283.58

RECTIFIER REGULATOR

SOLENOID

SHIFT

STARTER

30˚

PILOT 177.800 (7.000) OPTIONAL PILOT 146.050 (5.750)

ENGINE MOUNTING SURFACE

155.58 (6.125)

Figure 1-5. Typical Engine Dimensions with Low-Proﬁ le Air Cleaner.

334.78

(13.180)

173.68 (6.838)

65.00

(2.559)

122.10 (4.807)

75.35

(2.966)

MOUNTING HOLE “A”

LIFT STRAP

M8 X 1.25 4 STUDS

M8 X 1.25

20.5 DEEP 2 HOLES MUFFLER MTG BOSSES

50.00

(1.969)

EXHAUST PORT #2

308.17

(12.133)

1.7

Section 1 Safety and General Information

General Speciﬁ cations¹

Power (@ 3600 RPM, exceeds Society of Automotive Engineers-Small Engine Test Code J1940.)

ECH630 .................................................................................................................................... 14.1 kW (19 HP)

ECH650 .................................................................................................................................... 15.7 kW (21 HP)

ECH680 .................................................................................................................................... 17.2 kW (23 HP)

ECH730 .................................................................................................................................... 18.6 kW (25 HP)

ECH740 .................................................................................................................................... 20.1 kW (27 HP)

ECH749 .................................................................................................................................... 21.6 kW (29 HP)

Bore

ECH630,ECH650,ECH680 .................................................................................................... 80 mm (3.15 in.)

ECH730,ECH740,ECH749..................................................................................................... 83 mm (3.27 in.)

Stroke .............................................................................................................................................. 69 mm (2.72 in.)

Displacement

ECH630,ECH650,ECH680 .................................................................................................... 694 cc (42.4 cu. in.)

ECH730,ECH740,ECH749..................................................................................................... 747cc (45.6 cu. in.)

Compression Ratio

ECH630,ECH650,ECH680..................................................................................................... 8.8:1

ECH730,ECH740,ECH749..................................................................................................... 9.1:1

Dry Weight ..................................................................................................................................... 46 kg (102 lb.)

Oil Capacity (w/ﬁ lter) - approximate, determined by oil ﬁ lter and oil cooler used ........... 1.9 L (2.0 U.S. qt.)

Angle of Operation - Maximum (At Full Oil Level) All Directions ....................................... 25°

Blower Housing Screws (into cored aluminum hole or weld nut)

M5 Fasteners Torque ....................................................................................... 6.2 N·m (55 in. lb.) into new holes

4.0 N·m (35 in. lb.) into used holes

M6 Fasteners Torque ....................................................................................... 10.7 N·m (95 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Blower Housing Screws (into extruded hole or sheet metal)

M5 Fasteners Torque ....................................................................................... 2.8 N·m (25 in. lb.) into new holes

2.3 N·m (20 in. lb.) into used holes

M6 Fasteners Torque ....................................................................................... 2.8 N·m (25 in. lb.) into new holes

2.3 N·m (20 in. lb.) into used holes

Rectiﬁ er-Regulator Ground Strap Fastener Torque ...................................2.8 N·m (25 in. lb.) into new holes

2.3 N·m (20 in. lb.) into used holes

Blower Housing Screws

Rectiﬁ er-Regulator Fastener Torque ............................................................. 1.4 N·m (12.6 in. lb.)

¹Values are in Metric units. Values in parentheses are English equivalents. Lubricate threads with engine oil prior to assembly.

1.8

Section 1

Safety and General Information

Camshaft

End Play (No Shim) ........................................................................................ 0.101/0.406 mm (0.0040/0.0160 in.)

Running Clearance .......................................................................................... 0.025/0.105 mm (0.001/0.004 in.)

Bore I.D.

New ............................................................................................................ 20.000/20.025 mm (0.7874/0.7884 in.)

Max. Wear Limit ....................................................................................... 20.038 mm (0.7889 in.)

Camsha Bearing Surface O.D.

New ............................................................................................................ 19.920/19.975 mm (0.7843/0.7864 in.)

Max. Wear Limit ....................................................................................... 19.914 mm (0.7840 in.)

Connecting Rod

Cap Fastener Torque (torque in increments)............................................... 11.6 N·m (103 in. lb.)

Connecting Rod-to-Crankpin Running Clearance @ 21°C (70°F)

New ............................................................................................................ 0.043/0.073 mm (0.0017/0.0029 in.)

Max. Wear Limit ....................................................................................... 0.088 mm (0.0035 in.)

Connecting Rod-to-Crankpin Side Clearance ............................................. 0.26/0.63 mm (0.0102/0.0248 in.)

Connecting Rod-to-Piston Pin Running Clearance @ 21°C (70°F) .......... 0.015/0.028 mm (0.0006/0.0011 in.)

Piston Pin End I.D. @ 21°C (70°F)

New ............................................................................................................ 17.015/17.023 mm (0.6699/0.6702 in.)

Max. Wear Limit ....................................................................................... 17.036 mm (0.6707 in.)

Crankcase

Governor Cross Sha Bore I.D.

New ............................................................................................................ 8.025/8.075 mm (0.3159/0.3179 in.)

Max. Wear Limit ....................................................................................... 8.088 mm (0.3184 in.)

Breather Cover Fastener Torque ................................................................... 11.3 N·m (100 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Oil Temperature Sensor Torque (into breather cover) ............................... 7.3 N·m (65 in. lb.)

Oil Sentry Torque (into breather cover) ....................................................... 4.5 N·m (40 in. lb.)

Oil Drain Plug Torque ....................................................................................13.6 N·m (10  . lb.)

Closure Plate

Closure Plate Fastener Torque ...................................................................... 25.6 N·m (227 in. lb.)

1.9

Section 1 Safety and General Information

Crankshaft

Non-Thrust Bearing End Play (Free) ............................................................ 0.070/0.590 mm (0.0028/0.0230 in.)

Thrust Bearing End Play (Free) ..................................................................... 0.070/0.270 mm (0.0028/0.0100 in.)

Cranksha Bore (In Crankcase)

New ............................................................................................................ 40.972/40.997 mm (1.6131/1.6141 in.)

Max. Wear Limit ....................................................................................... 41.011 mm (1.6146 in.)

Cranksha to Sleeve Bearing (Closure Plate)

Running Clearance - New ...................................................................... 0.03/0.12 mm (0.001/0.005 in.)

Cranksha Bore (In Closure Plate) - New ................................................... 40.974/41.000 mm (1.6131/1.6141 in.)

Cranksha Bore (In Closure Plate)-to-Cranksha

Running Clearance - New ...................................................................... 0.039/0.087 mm (0.0015/0.0034 in.)

Flywheel End Main Bearing Journal

O.D. - New ................................................................................................ 40.913/40.935 mm (1.6107/1.6116 in.)

O.D. - Max. Wear Limit ...........................................................................40.843 mm (1.608 in.)

Max. Taper Limit ...................................................................................... 0.022 mm (0.0009 in.)

Max. Out-of-Round Limit ....................................................................... 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 Limit ...................................................................................... 0.022 mm (0.0009 in.)

Max. Out-of-Round Limit ....................................................................... 0.025 mm (0.0010 in.)

Connecting Rod Journal

O.D. - New ................................................................................................ 35.950/35.973 mm (1.4153/1.4163 in.)

O.D. - Max. Wear Limit ...........................................................................35.941 mm (1.415 in.)

Max. Taper Limit ...................................................................................... 0.018 mm (0.0007 in.)

Max. Out-of-Round Limit ....................................................................... 0.025 mm (0.0010 in.)

Cranksha 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 - ECH630,ECH650,ECH680 ........................................................... 80.000/80.025 mm (3.1496/3.2689 in.)

New - ECH730,ECH740,ECH749 ........................................................... 83.006/83.031 mm (3.2680/3.2689 in.)

Max. Wear Limit - ECH630,ECH650,ECH680...................................... 80.075 mm (3.1526 in.)

Max. Wear Limit - ECH730,ECH740,ECH749...................................... 83.081 mm (3.2709 in.)

Max. Out-of-Round .................................................................................0.120 mm (0.0047 in.)

Max. Taper ................................................................................................ 0.05 mm (0.0020 in.)

1.10

Safety and General Information

Cylinder Head

Cylinder Head Fastener Torque

Hex Flange Nut - Torque in Two Stages ............................................... ﬁ rst to 16.9 N·m (150 in. lb.)

ﬁ nally to 33.9 N·m (300 in. lb.)

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

ﬁ nally to 41.8 N·m (370 in. lb.)

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

Rocker Arm Screw Torque ............................................................................. 11.9 N·m (105 in. lb.)

Fan/Flywheel

Fan Fastener Torque........................................................................................ 9.9 N·m (88 in. lb.)

Flywheel Retaining Screw Torque ................................................................ 71.6 N·m (52.8  . lb.)

Metal Grass Screen Fastener Torque (to Flywheel) .................................... 9.9 N·m (88 in. lb.)

Plastic Grass Screen Fastener Torque (to Fan) ........................................... 4.0 N·m (35 in. lb.)

Section 1

Fuel Pump

Fuel Pump Module Baﬄ e Fastener Torque ................................................. 11.9 N·m (105 in. lb.)

Fuel Pump Module Fastener Torque ............................................................ 9.2 N·m (81 in. lb.)

Pulse Pump Bracket Fastener Torque .......................................................... 2.1 N·m (25 in. lb.)

Pulse Pump Fastener to Bracket Torque ...................................................... 7.3 N·m (68 in. lb.) into new holes

6.2 N·m (55 in. lb.) into used holes

Governor

Governor Cross Sha -to-Crankcase Running Clearance .......................... 0.025/0.126 mm (0.0009/0.0049 in.)

Governor Cross Sha O.D.

New ............................................................................................................ 7.949/8.000 mm (0.3129/0.3149 in.)

Max. Wear Limit ....................................................................................... 7.936 mm (0.3124 in.)

Governor Gear Sha -to-Governor Gear Running Clearance ................... 0.090/0.160 mm (0.0035/0.0063 in.)

Governor Gear Sha 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 .......................................................................... 7.1 N·m (63 in. lb.)

Governor Speed Control Assembly Torques

Assembled to Cylinder Heads ............................................................... 10.7 N·m (95 in. lb.)

Assembled to Blower Housing .............................................................. 2.8 N·m (25 in. lb.)

1.11

Section 1 Safety and General Information

Ignition

Spark Plug Type (Champion® or Equivalent) ............................................. RC12YC, XC12YC, or Platinum 3071

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

Spark Plug Torque........................................................................................... 24.4-29.8 N·m (18-22  . lb.)

Ignition Coil Fastener Torque ........................................................................ 10.2 N·m (90 in. lb.)

Cranksha Position Sensor Screw Torque ................................................... 6.2 N·m (55 in. lb.)

Cranksha Position Sensor Bracket Screw Torque .................................... 7.3 N·m (65 in. lb.)

Cranksha Position Sensor Air Gap ............................................................. 0.2-0.7 mm (0.008-0.027 in.)

Electronic Control Unit Screw Torque .........................................................6.2 N·m (55 in. lb.)

Intake Manifold

Intake Manifold Mounting Fastener Torque

Torque in Two Stages ..............................................................................ﬁ rst to 7.8 N·m (69 in. lb.)

ﬁ nally to 10.5 N·m (93 in. lb.)

Manifold Absolute Pressure (MAP) Sensor Fastener Torque ................... 7.3 N·m (65 in. lb.)

Fuel Injector Cap Torque ................................................................................ 7.3 N·m (65 in. lb.)

Air Cleaner to Thro le Body Fastener Nut Torque .................................... 8.2 N·m (73 in. lb.)

Heavy-Duty Air Cleaner Mounting Bracket Fastener Torque .................. 5.8 N·m (51 in. lb.)

Mufﬂ er

Muﬄ er Retaining Nut Torque....................................................................... 27.8 N·m (246 in. lb.)

Oxygen Sensor Torque ................................................................................... 50.1 N·m (37  . lb.)

Oil Filter

Oil Filter Torque .............................................................................................. refer to the oil ﬁ lter for instructions

Oil Cooler

Oil Cooler/Adapter Nipple Torque .............................................................. 28.5 N·m (21  . lb.)

Oil Cooler Fastener Torque

Into Blower Housing ............................................................................... 2.8 N·m (25 in. lb.)

Between Oil Cooler Hoses ...................................................................... 2.3 N·m (20 in. lb.)

1.12

Section 1

Safety and General Information

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 .................................... 0.050/0.095 mm (0.0019/0.0037 in.)

Middle Compression Ring-to-Groove Side Clearance .............................. 0.030/0.075 mm (0.0012/0.00307 in.)

Oil Control Ring-to-Groove Side Clearance ................................................ 0.010/0.011 mm (0.0004/0.0043 in.)

Top and Center Compression Ring End Gap

New ............................................................................................................ 0.025/0.056 mm (0.0010/0.0022 in.)

Max. Wear Limit - ECH630,ECH650,ECH680 ..................................... 0.80 mm (0.0315 in.)

Max. Wear Limit - ECH730,ECH740,ECH749...................................... 0.94 mm (0.037 in.)

Piston Thrust Face O.D.

ECH630,ECH650,ECH680....................................................................... 79.962/79.980 mm (3.1481/3.1488 in.)

ECH730,ECH740,ECH749....................................................................... 82.949/82.967 mm (3.2657/3.2664 in.)

Max. Wear Limit - ECH630,ECH650,ECH680...................................... 79.831 mm (3.1430 in.)

Max. Wear Limit - ECH730,ECH740,ECH749...................................... 82.818 mm (3.2606 in.)

Piston Thrust Cylinder-to-Bore2 Running Clearance

New - ECH630,ECH650,ECH680 ........................................................... 0.020/0.063 mm (0.0008/0.0024 in.)

New - ECH730,ECH740,ECH749 ........................................................... 0.0039/0.082 mm (0.0015/0.0032 in.)

Speed Control Bracket (Assembled to Cylinder Heads)

Fastener Torque ...............................................................................................10.7 N·m (95 in. lb.) into new holes

7.3 N·m (65 in. lb.) into used holes

Speed Control Bracket (Assembled to Blower Housing)

Fastener Torque ...............................................................................................2.8 N·m (25 in. lb.) into new holes

2.3 N·m (20 in. lb.) into used holes

Starter Assembly

Thru Bolt Torque .............................................................................................5.6-9.0 N·m (49-79 in. lb.)

Mounting Screw Torque (All)........................................................................ 16.0 N·m (142 in. lb.)

Brush Holder Mounting Screw Torque........................................................ 2.5-3.3 N·m (22-29 in. lb.)

Starter Solenoid

Mounting Hardware Torque .........................................................................4.0-6.0 N·m (35-53 in. lb.)

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

² Measure 6 mm (0.236 in.) above the bo om of the piston skirt at right angles to the piston pin.

1.13

Section 1 Safety and General Information

Stator

Mounting Screw Torque ................................................................................. 6.2 N·m (55 in. lb.) into new holes

4.0 N·m (35 in. lb.) into used holes

Valve Cover

Valve Cover Fastener Torque.........................................................................6.2 N·m (55 in. lb.)

Valves and Valve Lifters

Hydraulic Li er to Crankcase Running Clearance .................................... 0.011/0.048 mm (0.0004/0.0019 in.)

Intake Valve Stem-to-Valve Guide Running Clearance ............................. 0.040/0.078 mm (0.0016/0.0031 in.)

Exhaust Valve Stem-to-Valve Guide Running Clearance .......................... 0.052/0.090 mm (0.0020/0.0035 in.)

Intake Valve Guide I.D.

New ............................................................................................................ 7.040/7.060 mm (0.2772/0.2780 in.)

Max. Wear Limit ....................................................................................... 7.134 mm (0.2809 in.)

Exhaust Valve Guide I.D.

New ............................................................................................................ 7.040/7.060 mm (0.2772/0.2780 in.)

Max. Wear Limit ....................................................................................... 7.159 mm (0.2819 in.)

Valve Guide Reamer Size

Standard .................................................................................................... 7.050 mm (0.2776 in.)

0.25 mm O.S. ............................................................................................. 7.300 mm (0.2874 in.)

Intake Valve Minimum Li ........................................................................... 8.07 mm (0.3177 in.)

Exhaust Valve Minimum Li ........................................................................ 8.07 mm (0.3177 in.)

Nominal Valve Seat Angle ............................................................................. 45°

1.14

Safety and General Information

General Torque Values

Metric Fastener Torque Recommendations for Standard Applications

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

Section 1

Property Class

4.8

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%

4.8

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

Property Class

8.8

10.9

12.9

Noncritical

Fasteners

Into Aluminum

Noncritical

Fasteners

Into Aluminum

1.15

Section 1 Safety and General Information

English Fastener Torque Recommendations for Standard Applications

Tightening Torque: N·m (in. lb.) + or - 20%

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

Grade 2 Grade 5 Grade 8

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) --------- --------- ---------

Tightening Torque: N·m (ft. lb.) + or - 20%

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) ---------

Grade 2 or 5

Fasteners Into

Aluminum

1.16

Torque

Conversions

N·m = in. lb. x 0.113 N·m =  . lb. x 1.356 in. lb. = N·m x 8.85  . lb. = N·m x 0.737

Section 2

Tools & Aids

Certain quality tools are designed to help you perform speciﬁ c 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.

Tools Description Source/Part No.

Camsha Endplay Plate

For checking camsha endplay.

Camsha Seal Protector (Aegis)

To protect seal during camsha installation.

Cylinder Leakdown Tester

For checking combustion retention and if cylinder, piston, rings, or valves are worn.

Electronic Fuel Injection (EFI) Diagnostic So ware

Use with Laptop or Desktop PC.

EFI Service Kit

For troubleshooting and se ing up an EFI engine.

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

Design Technology Inc. 768 Burr Oak Drive Westmont, IL 60559 Phone 630-920-1300 Fax 630-920-0011

SE Tools KLR-82405

SE Tools KLR-82417

Kohler 25 761 05-S

Kohler 25 761 23-S

Kohler 24 761 01-S

Individual Components Available Fuel Pressure Tester Noid Light 90° Adapter In-line "T" Fi ing Code Plug, Red Wire Code Plug, Blue Wire Shrader Valve Adapter Hose

Flywheel Holding Tool (CS Series) SE Tools KLR-82407

Flywheel Puller

To remove ﬂ ywheel from engine.

Flywheel Strap Wrench

To hold ﬂ ywheel during removal.

Design Technology Inc.

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

SE Tools KLR-82408

SE Tools KLR-82409

2.1

Section 2 Tools & Aids

Tools (Continued)

Description Source/Part No.

Hydraulic Valve Li er Tool

To remove and install hydraulic li ers.

Ignition System Tester

For testing output on all systems, including CD.

Oﬀ set Wrench (K & M Series)

To remove and reinstall cylinder barrel retaining nuts.

Oil Pressure Test Kit

To test and verify oil pressure.

Rectiﬁ er-Regulator Tester (120 volt current) Rectiﬁ er-Regulator Tester (240 volt current)

Used to test rectiﬁ er-regulators.

Kohler 25 761 38-S

Kohler 25 455 01-S

Kohler 52 455 04-S

Kohler 25 761 06-S

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

Individual Components Available CS-PRO Regulator Test Harness Special Regulator Test Harness with Diode

Spark Advance Module (SAM) Tester

To test the SAM (ASAM and DSAM) on engines with SMART-SPARK™.

Starter Servicing Kit (All Starters)

To remove and reinstall drive retaining rings and brushes.

Individual Component Available Starter Brush Holding Tool (Solenoid Shi )

Tachometer (Digital Inductive)

For checking operating speed (RPM) of an engine.

Vacuum/Pressure Tester

Alternative to a water manometer.

Design Technology Inc.

DTI-031 DTI-033

Kohler 25 761 40-S

SE Tools KLR-82411

SE Tools KLR-82416

Design Technology Inc.

DTI-110

Kohler 25 761 22-S

2.2

Section 2

Tools & Aids

Aids

Description Source/Part No.

Camsha Lubricant (Valspar ZZ613) Kohler 25 357 14-S

Dielectric Grease (GE/Novaguard G661) Kohler 25 357 11-S

Dielectric Grease (Fel-Pro) Lubri-Sel

Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S

Electric Starter Drive Lubricant (Solenoid Shi ) Kohler 52 357 02-S

RTV Silicone Sealant

Loctite® 5900 Heavy Body in 4 oz aerosol dispenser. Only oxime-based, oil resistant RTV sealants, such as those listed, are approved for use. Loctite® Nos. 5900® or 5910® are recommended for best sealing characteristics.

Loctite® 5910® Loctite® Ultra Black 598™ Loctite® Ultra Blue 587™ Loctite® Ultra Copper 5920™

Spline Drive Lubricant Kohler 25 357 12-S

Kohler 25 597 07-S

2.3

Section 2 Tools & Aids

Special Tools You Can Make

Flywheel Holding Tool

A ﬂ ywheel holding tool can be made out of an old ﬂ ywheel 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 bosses will lock the tool and ﬂ ywheel in posi- tion 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 ﬂ at.

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

4. Use a ﬂ at washer with the correct I.D. to slip on the capscrew and approximately 1 in. 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/Crankshaft Tool.

2.4

Section 3

Troubleshooting

Troubleshooting Guide

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

Some general common causes of engine troubles are listed below. Use these to locate the causing factors. Refer to the speciﬁ c section(s) within this service manual for more detailed information.

Engine Cranks But Will Not Start

1. Empty fuel tank.

2. Fuel shut-oﬀ valve closed.

3. Poor fuel, dirt or water in the fuel system.

4. Clogged fuel line.

5. Spark plug lead(s) disconnected.

6. Key switch or kill switch in OFF position.

7. Faulty spark plugs.

8. Faulty ignition coil(s).

9. Vacuum fuel pump malfunction, or oil in vacuum hose.

10. Vacuum hose to fuel pump leaking or cracked.

11. Ba ery connected backwards.

12. Safety interlock system engaged.

13. Blown fuse.

14. Faulty electronic control unit.

15. Insuﬃ cient voltage to electronic control unit.

Engine Starts But Does Not Keep Running

1. Restricted fuel tank cap vent.

2. Poor fuel, dirt or water in the fuel system.

3. Faulty or improperly adjusted thro le controls.

4. Loose wires or connections.

5. Faulty cylinder head gasket.

6. Vacuum fuel pump malfunction, or oil in vacuum hose.

7. Vacuum hose to fuel pump leaking or cracked.

8. Intake system leak.

9. Faulty ignition coil(s).

10. Blown fuse.

11. Insuﬃ cient voltage to electronic control unit.

Engine Starts Hard

1. PTO drive is engaged.

2. Dirt or water in the fuel system.

3. Clogged fuel line or fuel ﬁ lter.

4. Loose or faulty wires or connections.

5. Faulty or improperly adjusted thro le controls.

6. Faulty spark plugs.

7. Low compression.

8. Weak spark.

9. Fuel pump malfunction causing lack of fuel.

10. Engine overheated-cooling/air circulation restricted.

11. Quality of fuel.

12. Flywheel key sheared.

13. Intake system leak.

Engine Will Not Crank

1. PTO drive is engaged.

2. Ba ery 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.

7. Seized internal engine components.

8. Blown fuse.

9. Faulty electronic control unit.

10. Insuﬃ cient voltage to electronic control unit.

Engine Runs But Misses

1. Dirt or water in the fuel system.

2. Spark plug lead disconnected.

3. Poor quality of fuel.

4. Faulty spark plug(s).

5. Loose wires or connections.

6. Engine overheated.

7. Faulty ignition module.

8. Incorrect cranksha position sensor air gap.

9. Insuﬃ cient voltage to electronic control unit.

Engine Will Not Idle

1. Dirt or water in the fuel system.

2. Stale fuel or dirty fuel injectors.

3. Faulty spark plugs.

4. Inadequate fuel supply.

5. Low compression.

6. Restricted fuel tank cap vent.

7. Engine overheated-cooling system/air circulation problem.

3.1

Section 3 Troubleshooting

Engine Overheats

1. Air intake/grass screen, cooling ﬁ ns, oil cooler, or cooling shrouds clogged.

2. Excessive engine load.

3 Low crankcase oil level.

4. High crankcase oil level.

5. Lean air-fuel mixture.

Engine Knocks

1. Excessive engine load.

2. Low crankcase oil level.

3. Old or improper fuel.

4. Internal wear or damage.

5. Hydraulic li er malfunction.

6. Quality of fuel.

7. Incorrect grade of oil.

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 overheated.

7. Faulty spark plugs.

8. Low compression.

9. Exhaust restriction.

10. Low ba ery.

11. Incorrect governor se ing.

 • Check for buildup of dirt and debris on the

crankcase, cooling ﬁ ns, grass screen, and other external surfaces. Dirt or debris on these areas are causes of higher operating temperatures and overheating.

 • Check for obvious fuel and oil leaks, and

damaged components. Excessive oil leakage can indicate a clogged or improperly-assembled breather, worn/damaged seals and gaskets, or loose or improperly-torqued fasteners.

 • Check the air cleaner cover and base for damage

or indications of improper ﬁ t and seal.

 • Check the air cleaner element. Look for holes,

tears, cracked or damaged sealing surfaces, or other damage that could allow unﬁ ltered air into the engine. Also note if the element is dirty or clogged. These could indicate that the engine has been under serviced.

 • Check the oil level. Note if the oil level is within

the operating range on the dipstick, or if it is low or overﬁ lled.

 • Check the condition of the oil. Drain the oil into

a container - the oil should ﬂ ow freely. Check for metal chips and other foreign particles.

Engine Uses Excessive Amount of Oil

1. Incorrect oil viscosity/type.

2. Clogged or improperly assembled breather.

3. Breather reed broken.

4. Worn or broken piston rings.

5. Worn cylinder bore.

6. Worn valve stems/valve guides.

7. Crankcase overﬁ lled.

8. Blown head gasket/overheated.

Oil Leaks from Oil Seals, Gaskets

1. Crankcase breather is clogged or inoperative.

2. Breather reed broken.

3. Loose or improperly torqued fasteners.

4. Piston blowby or leaky valves.

5. 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.

Sludge is a natural by-product of combustion; a

small accumulation is normal. Excessive sludge formation could indicate overrich fuel se ings, weak ignition, over-extended oil change interval or wrong weight or type of oil was used, 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

A er 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.

3.2

Section 3

Troubleshooting

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. Pressure in the crankcase (normally caused by a clogged or improperly assembled breather) can cause oil to be forced out at oil seals, gaskets, or other available spots.

Crankcase vacuum is best measured with either a water manometer or a vacuum gauge (see Section 2). Complete instructions are provided in the kits.

To test the crankcase vacuum with the manometer:

1. Insert the stopper/hose into the oil ﬁ ll hole. Leave the other tube of manometer open to atmosphere. Make sure the shut oﬀ clamp is closed.

2. Start the engine and run at no-load high speed (3200-3750 RPM).

3. Open the clamp and note the water level in the tube.

4. Close the shut oﬀ clamp before stopping the

engine.

To test the crankcase vacuum with the Vacuum/ Pressure Gauge Kit (see Section 2):

1. Remove the dipstick or oil ﬁ ll plug/cap.

2. Install the adapter into the oil ﬁ ll/dipstick tube opening, upside down over the end of a small diameter dipstick tube, or directly into engine if a tube is not used.

3. Push the barbed ﬁ  ing on the gauge solidly into the hole in the adapter.

4. Start the engine and bring it up to operating speed (3200-3600 RPM).

5. Check the reading on the gauge. If the reading is to the le of “0” on the gauge, vacuum or negative pressure is indicated. If the reading is to the right of “0” on the gauge, positive pressure is present.

Crankcase vacuum should be 4-10 (inches of water) If the reading is below speciﬁ cation, or if pressure is present, check the following table for possible causes and remedies.

The level in the engine side should be a minimum

of 10.2 cm (4 in.) above the level in the open side.

If the level in the engine side is less than speciﬁ ed

(low/no vacuum), or the level in the engine side is lower than the level in the open side (pressure), check for the conditions in the table below.

No Crankcase Vacuum/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 (conﬁ rm by inspecting components).

Solution

1. Disassemble breather, clean parts thoroughly, check sealing surfaces for ﬂ atness, 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. Restricted exhaust.

4. Repair/replace restricted muﬄ er/exhaust system.

3.3

Section 3 Troubleshooting

Compression Test

A compression test can be performed using a compression tester. Follow the manufacturers instructions for performing the test.

Cylinder Leakdown Test

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

Cylinder Leakdown Tester (see Section 2) is a relatively simple, inexpensive leakdown tester for small engines. The tester includes a quick disconnect for a aching the adapter hose, and a holding tool.

Leakdown Test Instructions

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

2. Remove spark plug(s) and air ﬁ lter from engine.

3. Rotate the cranksha until the piston (of cylinder being tested) is at top dead center of the compression stroke. Hold the engine in this position while testing. The holding tool supplied with the tester can be used if the PTO end of the cranksha is accessible. Lock the holding tool onto the cranksha . Install a 3/8 in. breaker bar into the hole/slot of the holding tool, so it is perpendicular to both the holding tool and cranksha PTO.

If the ﬂ ywheel end is more accessible, use a

breaker bar and socket on the ﬂ ywheel nut/ screw to hold it in position. An assistant may be needed to hold the breaker bar during testing. If the engine is mounted in a piece of equipment, it may be possible to hold it by clamping or wedging a driven component. Just be certain that the engine cannot rotate oﬀ of TDC in either direction.

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

5. Connect an air source of at least 50 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 the tester quick-disconnect to the adapter hose while ﬁ rmly holding the engine at TDC. Note the gauge reading and listen for escaping air at the thro le body intake, exhaust outlet, and crankcase breather.

8. Check your test results against the following table:

Leakdown Test Results

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

Air escaping from exhaust system .........................................Defective exhaust valve/improper seating.

Air escaping from thro le body..............................................Defective intake valve/improper seating.

Gauge reading in Low (green) zone .......................................Piston rings and cylinder in good condition.

Gauge reading in Moderate (yellow) zone ...........................Engine is still usable, but there is some wear present.

Customer should start planning for overhaul or replacement.

Gauge reading in High (red) zone .........................................Rings and/or cylinder have considerable

should be reconditioned or replaced.

3.4

wear. Engine

Section 4

Air Cleaner and Air Intake System

Section 4

Air Cleaner and Air Intake System

This engine is equipped with heavy-duty air cleaner, low-proﬁ le air cleaner, or special air cleaner supplied by the equipment manufacturer.

Heavy-Duty Air Cleaner

General

The heavy-duty air cleaner consists of a cylindrical housing, typically mounted to a bracket oﬀ the upper valve cover screws, and mounted to the thro le body/intake manifold. The air cleaner housing contains a paper element and inner element, designed for longer service intervals. The system is CARB/EPA certiﬁ ed and the components should not be altered or modiﬁ ed in any way.

Figure 4-1. Heavy-Duty Air Cleaner Assembly.

Figure 4-2. Heavy-Duty Air Cleaner Exploded View.

Cover

A - Filter End Cap B - Outer Element C - Inner Element D - Air Cleaner Housing E - Rain Cover Cap F - Filter Minder G - Inlet Screen H - Retaining Clip

Service

Weekly and every 150 hours: Check ﬁ lter minder (if equipped), perform inspection of the paper element, and inlet screen area. See Figure 4.2.

Yearly or every 300 hours of operation (more o en under extremely dusty or dirty conditions), replace the paper element and check the inner element.

1. Unhook the two retaining clips (A) on each end and remove the end caps (E) from the air cleaner

housing (D). See Figures 4-1 and 4-2.

2. Check and clean the inlet screen (G).

3. Pull the elements out of the housing on the opposite side. See Figure 4-2. A er the outer element (B) is removed, check the condition of the inner element (C). It should be replaced whenever it appears dirty, typically every other time the main element is replaced, or every 600 hours. Clean the area around the base of the inner element (C) before removing it, so dirt does not get into the engine.

4.1

Section 4 Air Cleaner and Air Intake System

4. Do not wash the outer element (B) and inner element (C), or use compressed air as this will damage the elements. Replace dirty, bent or

damaged elements with new genuine Kohler elements as required. Handle the new elements carefully; do not use if the sealing surfaces are bent or damaged.

5. Check all parts for wear, cracks, or damage, and make sure ejector area is clean. See Figure 4-3. Replace any damaged components.

Figure 4-3. Ejector Area.

6. Install the new inner element (C), followed by the outer element (B). Slide each fully into place in the air cleaner housing (D). See Figure 4-2.

7. Reinstall the end caps (A) and secure with the retaining clips (H). See Figure 4-2.

Removal

1. Remove the three hex ﬂ ange nuts securing the assembly to the thro le body. See Figure 4-4.

2. Remove the two hex ﬂ ange screws securing the air cleaner assembly to air cleaner bracket. See Figure 4-5.

Figure 4-5. Heavy-Duty Air Cleaner Bracket.

3. Li the entire air cleaner assembly oﬀ the engine. Disassemble or service as required.

4. Reinstall the components in reverse order of removal. Torque the air cleaner hex ﬂ ange nuts to

8.3 N·m (73 in. lb.). Torque the air cleaner bracket screws to 58 N·m (51 in. lb.).

5. Reset the governor (refer to Section 5).

Low-Proﬁ le Air Cleaner (Optional)

General

An optional air cleaner is the low-proﬁ le air cleaner with an oiled-foam precleaner which surrounds a paper element.

The low-proﬁ le air cleaner is shown in Figure 4-6.

Figure 4-4. Air Cleaner Hex Flange Nuts.

4.2

Figure 4-6. Low-Proﬁ le Air Cleaner.

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