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

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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.

Service

Check the air cleaner daily or before starting the engine. Check for and correct any buildup of dirt and

debris, along with loose or damaged components.

Section 4

Air Cleaner and Air Intake System

NOTE: Operating the engine with loose or

damaged air cleaner components could allow unﬁ ltered air into the engine causing premature wear and failure.

Precleaner Service

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

or dirty conditions).

To service the precleaner, see Figures 4-7, 4-8 and 4-9 and perform the following steps:

Cover

Element Cover

Retaining Knob

Wing Nut

Stud Seal

Air Cleaner Base

Precleaner Element

Air Cleaner Element

Bracket Mounting Screws

Figure 4-9. Base Plate Removal on Low-Proﬁ le Air Cleaner.

1. Loosen the cover retaining knob and remove the cover.

2. Remove the foam precleaner from the paper air cleaner element.

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. Reinstall the precleaner over the paper air cleaner element.

6. Reinstall the air cleaner cover. Secure the cover with the retaining knob.

Mounting Nuts (3)

Figure 4-7. Low-Proﬁ le Air Cleaner Exploded View.

Air Cleaner Element

Precleaner Element

Figure 4-8. Precleaner on Low-Proﬁ le Air Cleaner.

Paper Element Service

Every 100 hours of operation (more o en under extremely dusty or dirty conditions), replace the paper element. See Figure 4-8, and follow these steps:

1. Loosen the cover retaining knob and remove the cover.

2. Remove the wing nut, element cover, and air cleaner element.

3. Remove the precleaner from the paper element. Service the precleaner as described in Precleaner Service.

4.3

Section 4 Air Cleaner and Air Intake System

4. 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.

5. Check the rubber sleeve seal for any damage or deterioration. Replace as necessary.

6. Reinstall the paper element, precleaner, element cover, and wing nut.

7. Reinstall the air cleaner cover and secure retaining knob.

Air Cleaner Components

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

Air Cleaner Element Cover and Seal - Make sure element cover is not bent or damaged. Make sure the rubber sleeve seal is in place on the stud to prevent dust or dirt entry through the stud hole.

Air Intake/Cooling System

To ensure proper cooling, make sure the ﬁ xed screen, cooling ﬁ ns, and other external surfaces of the engine are kept clean at all times.

Every 100 hours of operation (more o en under extremely dusty or dirty conditions), remove the blower housing and other cooling shrouds. Clean the cooling ﬁ ns and external surfaces as necessary. Make sure the cooling shrouds are reinstalled.

Kohler Cleanout kits are recommended to aid inspection and cleanout of the cooling ﬁ ns. See Figure 4-10.

NOTE: Operating the engine with a blocked ﬁ xed

screen, dirty or plugged cooling ﬁ ns, and/or cooling shrouds removed, will cause engine damage due to overheating.

Air Cleaner Base - Make sure the base is secured tightly to the thro le body and not cracked or damaged.

NOTE: Damaged, worn or loose air cleaner

components can allow unﬁ ltered air into the engine causing premature wear and failure. Tighten or replace all loose or damaged components.

Disassembly/Reassembly - Low-Proﬁ le Air Cleaner

If the base plate on the low-proﬁ le air cleaner has to be removed, proceed as follows:

1. Remove the air cleaner components from the base (see Figures 4-7 and 4-8).

2. Remove the two hex ﬂ ange screws securing base to the bracket and the three hex ﬂ ange nuts from the studs from the intake manifold. See Figure 4-9.

3. Remove the base and gasket.

4. Reverse the procedure to reassemble the components. Torque the three hex ﬂ ange nuts to

7.4-9.0 N·m (65.5-80 in. lb.) and the two lower mounting screws to 2.8 N·m (25 in. lb.) into new holes or 2.3 N·m (20 in. lb.) into used holes.

Figure 4-10. Cleanout Kit Installed on Blower Housing.

5. Reset the governor (see Section 5).

4.4

Section 5

EFI Fuel System

Section 5

Electronic Fuel Injection (EFI)

System

Contents Page(s)

Description

Fuel Pump Module Connector Removal ................................................................................................................. 5.2

Initial Starting/Priming Procedure ........................................................................................................................... 5.2

Fuel Recommendations .............................................................................................................................................. 5.2

EFI Fuel System Components ................................................................................................................................... 5.3

Operation...................................................................................................................................................................... 5.3

Important Service Notes ......................................................................................................................................5.3-5.4

Electrical Components

Electronic Control Unit (ECU) ............................................................................................................................5.4-5.5

Wiring Harness ............................................................................................................................................................ 5.5

Electrical System ................................................................................................................................................... 5.5-5.8

Cranksha Position Sensor ........................................................................................................................................ 5.9

Thro le Position Sensor (TPS) and ECU Reset and TPS Learn Procedures ............................................... 5.9-5.11

Engine (Oil) Temperature Sensor ................................................................................................................... 5.11-5.12

Intake Air Temperature Sensor ............................................................................................................................... 5.12

Oxygen Sensor ................................................................................................................................................... 5.13-5.15

Manifold Absolute Pressure (MAP) Sensor .......................................................................................................... 5.16

Fuel Injectors ...................................................................................................................................................... 5.16-5.19

Ignition System .................................................................................................................................................. 5.19-5.20

Spark Plugs ................................................................................................................................................................ 5.20

Ba ery Charging System ......................................................................................................................................... 5.20

Fuel Components

Fuel Pump ..........................................................................................................................................................5.20-5.22

Fuel Filter ................................................................................................................................................................... 5.22

High Pressure Fuel Line ................................................................................................................................... 5.22-5.23

Purge Port and Vent Hose Assembly ..................................................................................................................... 5.23

Thro le Body/Intake Manifold Assembly ............................................................................................................. 5.23

Idle Speed Adjustment (RPM).........................................................................................................................5.23-5.24

Initial Governor Adjustment ...........................................................................................................................5.24-5.25

Troubleshooting

Troubleshooting Guide............................................................................................................................................. 5.26

Fuel System ........................................................................................................................................................ 5.26-5.27

Fault Codes .......................................................................................................................................................5.27-5.35

Troubleshooting Flow Chart............................................................................................................................5.35-5.36

Flow Chart Diagnostic Aids ............................................................................................................................5.37-5.38

EFI Service Tools ................................................................................................................................Refer to Section 2

5.1

Section 5 EFI Fuel System

Description

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

Explosive Fuel can cause ﬁ res and severe burns.

Fuel systems ALWAYS remains under HIGH PRESSURE.

Fuel Fire and Burns!

The EFI fuel system remains under high pressure even when the engine is stopped. Before a empting to service any part of the fuel system, the pressure must be relieved by following Fuel Pump Module Fuel Connector Removal instructions below.

Fuel Pump Module Fuel Connector Removal

Initial Starting/Priming Procedure

Important: The EFI fuel system must be purged of air (primed) prior to the initial start up, and/or any time the system has been disassembled or the fuel tank run dry.

2. A completely dry system may require repeating step 1 several times. Wait a minimum of 10 seconds between key OFF and key ON.

Fuel Recommendations

General Recommendations

Purchase gasoline in small quantities and store in clean, approved containers. An approved container with a capacity of 2 gallons or less with a pouring spout is recommended. Such a container is easier to handle and helps prevent spillage during refueling.

• 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

Gasoline/Alcohol Blends

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.

1. Turn the key switch to the ON/RUN position. You will hear the fuel pump cycle on and oﬀ . When the fuel pump stops cycling (approximately 20 seconds), the system is primed; start the engine.

5.2

Section 5

EFI Fuel System

EFI Fuel System Components

General

The Electronic Fuel Injection (EFI) system is a complete engine fuel and ignition management design. The system includes the following principal components:

• Fuel Pump Module and Li Pump

• Fuel Filter

• High Pressure Fuel Line

• Fuel Line(s)

• Fuel Injectors

• Thro le Body/Intake Manifold

• Electronic Control Unit (ECU)

• Ignition Coils

• Engine (Oil) Temperature Sensor

• Thro le Position Sensor (TPS)

• Cranksha Position Sensor

• Oxygen Sensor

• Manifold Absolute Pressure Sensor (MAP)

• Wire Harness Assembly & Aﬃ liated Wiring,

• Malfunction Indicator Light (MIL) - optional

• Intake Air Temperature Sensor

The ECU controls the amount of fuel being injected and the ignition timing by monitoring the primary sensor signals for engine temperature, speed (RPM), and thro le position (load). These primary signals are compared to preprogrammed maps in the ECU computer chip, and the ECU adjusts the fuel delivery to match the mapped values. A er the engine reaches operating temperature, an exhaust gas oxygen sensor provides feedback to the ECU based upon the amount of unused oxygen in the exhaust, indicating whether the fuel mixture being delivered is rich or lean. Based upon this feedback, the ECU further adjusts fuel input to re-establish the ideal air/fuel ratio. This operating mode is referred to as closed loop operation. The EFI system operates closed loop when all three of the following conditions are met:

a. The oil temperature is greater than 60°C (140°F).

b. The oxygen sensor has warmed suﬃ ciently to

provide a signal (minimum 400°C, 752°F).

c. Engine operation is at a steady state (not starting,

warming up, accelerating, etc.).

Operation

The EFI system is designed to provide peak engine performance with optimum fuel eﬃ ciency and lowest possible emissions. The ignition and injection functions are electronically controlled, monitored and continually corrected during operation to maintain the ideal air/fuel ratio.

The central component of the system is the Engine Control Unit (ECU) which manages system operation, determining the best combination of fuel mixture and ignition timing for the current operating conditions.

A li fuel pump is used to move fuel from the tank through an in-line fuel ﬁ lter and fuel line. The fuel is then pumped to the fuel pump module. The fuel pump module regulates fuel pressure to a system operating pressure of 39 psi. Fuel is delivered from the fuel pump module through the high pressure fuel line into the injectors, which inject the fuel into the intake ports. The ECU controls the amount of fuel by varying the length of time that the injectors are on. This can range from 2 to over 12 milliseconds depending on fuel requirements. The controlled injection of the fuel occurs every other cranksha revolution, or once for each 4-stroke cycle. When the intake valve opens, the air/fuel mixture is drawn into the combustion chamber, ignited, and burned.

During closed loop operation the ECU has the ability to readjust temporary and learned adaptive controls, providing compensation for changes in overall engine condition and operating environment, so it will be able to maintain the ideal air/fuel ratio. The system requires a minimum engine oil temperature greater than 80°C (176°F) to properly adapt. These adaptive values are maintained as long as the ECU is not reset.

During certain operating periods such as cold starts, warm up, acceleration, high load, etc., a richer air/ fuel ratio is required and the system operates in an open loop mode. In open loop operation the oxygen sensor output is used to ensure engine is running rich, and the controlling adjustments are based on the primary sensor signals and programmed maps only. The system operates open loop whenever the three conditions for closed loop operation (above) are not being met.

Important Service Notes!

• Cleanliness is essential and must be maintained at all times when servicing or working on the EFI system. Dirt, even in small quantities, can cause signiﬁ cant problems.

• Clean any joint or ﬁ  ing with parts cleaning solvent before opening to prevent dirt from entering the system.

5.3

Section 5 EFI Fuel System

• Always depressurize the fuel system through the fuel connector on fuel pump module before disconnecting or servicing any fuel system components. See fuel warning on page 5.2.

• Never a empt to service any fuel system component while the engine is running or the ignition switch is ON.

• Do not use compressed air if the system is open. Cover any parts removed and wrap any open joints with plastic if they will remain open for any length of time. New parts should be removed from their protective packaging just prior to installation.

• Avoid direct water or spray contact with system components.

• Do not disconnect or reconnect the ECU wiring harness connector or any individual components with the ignition on. This can send a damaging voltage spike through the ECU.

• Do not allow the ba ery cables to touch opposing terminals. When connecting ba ery cables a ach the positive (+) cable to the positive (+) ba ery terminal ﬁ rst, followed by the negative (-) cable to the negative (-) ba ery terminal.

Electrical Components

Electronic Control Unit (ECU)

Figure 5-1. Electronic Control Unit (ECU). General

The ECU is the brain or central processing computer of the entire EFI system. During operation, sensors continuously gather data which is relayed through the wiring harness to input circuits within the ECU. Signals to the ECU include: ignition (on/ oﬀ ), cranksha position and speed (RPM), thro le position, oil temperature, intake air temperature, exhaust oxygen levels, manifold absolute pressure, and ba ery voltage.

• Never start the engine when the cables are loose or poorly connected to the ba ery terminals.

• Never disconnect the ba ery while the engine is running.

• Never use a quick ba ery charger to start the engine.

• Do not charge the ba ery with the key switch ON.

• Always disconnect the negative (-) ba ery cable before charging the ba ery, and also unplug the harness from the ECU before performing any welding on the equipment.

The ECU compares the input signals to the programmed maps in its memory to determine the appropriate fuel and spark requirements for the immediate operating conditions. The ECU then sends output signals to set the injector duration and ignition timing.

The ECU continually performs a diagnostic check of itself, each of the sensors, and the system performance. If a fault is detected, the ECU can turn on a Malfunction Indicator Light (MIL) (if equipped) on the equipment control panel, store the fault code in its fault memory, and go into a default operating mode. Depending on the signiﬁ cance or severity of the fault, normal operation may continue. A technician can access the stored fault code using a blink code diagnosis ﬂ ashed out through the MIL. An optional computer so ware diagnostic program is also available, see Section 2.

The ECU requires a minimum of 6.0 volts to operate.

To prevent engine over-speed and possible failure, a rev-limiting feature is programmed into the ECU. If the maximum RPM limit (4500) is exceeded, the ECU suppresses the injection signals, cu ing oﬀ the fuel ﬂ ow. This process repeats itself in rapid succession, limiting operation to the preset maximum.

5.4

Section 5

EFI Fuel System

Service

Never a empt to disassemble the ECU. It is sealed to prevent damage to internal components. Warranty is void if the case is opened or tampered with in any way.

All operating and control functions within the ECU are preset. No internal servicing or readjustment may be performed. If a problem is encountered, and you determine the ECU to be faulty, contact your source of supply. Do not replace the ECU without factory authorization.

The ECU pins are coated at the factory with a thin layer of electrical grease to prevent fre ing and corrosion. Do not a empt to remove the grease from the ECU pins.

The relationship between the ECU and the thro le position sensor (TPS) is very critical to proper system operation. If the TPS or ECU is changed, or the mounting position of the TPS is altered, the appropriate TPS Learn Procedure (see page 5.11) must be performed to restore the synchronization.

Wiring Harness

The condition of the wiring, connectors, and terminal connections is essential to system function and performance. Corrosion, moisture, and poor connections are as likely the cause of operating problems and system errors as an actual component. Refer to the Electrical System section for additional information.

Electrical System

The EFI system is a 12 VDC negative ground system, designed to operate down to a minimum of 6.0 volts. If system voltage drops below this level, the operation of voltage sensitive components such as the ECU, fuel pump, ignition coils, and injectors will be intermi ent or disrupted, causing erratic operation or hard starting. A fully charged, 12 volt ba ery with a minimum of 350 cold cranking amps is important in maintaining steady and reliable system operation. Ba ery condition and state of charge should always be checked ﬁ rst when troubleshooting an operational problem.

Keep in mind that EFI-related problems are o en caused by the wiring harness or connections. Even small amounts of corrosion or oxidation on the terminals can interfere with the milliamp currents used in system operation.

Figure 5-2. ECU Connectors.

General

The wiring harness used in the EFI system connects the electrical components, providing current and ground paths for the system to operate. All input and output signaling occurs through two special all weather connectors that a ach and lock to the ECU. The connectors are Black and Grey and keyed diﬀ erently to prevent being a ached to the ECU incorrectly. See Figure 5-2.

1018

Cleaning the connectors and grounds will solve problems in many cases. In an emergency situation, simply disconnecting and reconnecting the connectors may clean up the contacts enough to restore operation, at least temporarily.

If a fault code indicates a problem with an electrical component, disconnect the ECU connector and test for continuity between the component connector terminals and the corresponding terminals in the ECU connector using an ohmmeter. Li le or no resistance should be measured, indicating that the wiring of that particular circuit is OK.

NOTE: When performing voltage or continuity

tests, avoid pu ing excessive pressure on or against the connector pins. Flat pin probes are recommended for testing to avoid spreading or bending the terminals.

5.5

Section 5 EFI Fuel System

Black Connector

Pin # Function

1 Ignition Coil #1 Ground 2Ba ery Ground 3 Diagnostic Communication Line 4 Speed Sensor input 5 Fuel Injector Output #1 Ground 6 Fuel Injector Output #2 Ground 7 Oxygen Sensor Heater 8 Intake Air Temperature (IAT) sensor input

9 Fuel Pump Ground 10 Ground for IAT, TPS, MAP, O2 and Oil Sensors 11 Manifold Absolute Pressure (MAP) sensor input 12 Thro le Position Sensor (TPS) input 13 Speed Sensor Ground 14 Oil Temperature Sensor input 15 Ignition Switch (Switched +12V) 16 Power for TPS and MAP Sensors (+5V) 17 Oxygen Sensor (O2) input 18 Ba ery Power (Permanent +12V)

Grey Connector

Pin # Description

1 Not Used 2 Not Used 3 Malfunction Indicator Light (MIL) Ground 4 Not Used 5 Not Used 6 Not Used 7 Not Used 8 Not Used

9Ba ery Ground 10 Ignition Coil #2 Ground 11 Not Used 12 Not Used 13 Not Used 14 Safety Switch Ground 15 Not Used 16 ECU 17 Fuel Pump Control (+12V) 18 Not Used

5.6

Pinout of the ECU

6-Terminal Connector

RectifierRegulator

1 2

6-Terminal Connector

DARK GREEN

DARK BLUE

BLACK

Battery

PURPLE

Stator

30A

1018

BLACK

Fuse

RED

RED/BLACK

PINK

Fuel Pump

RED/WHITE

31 2

TAN

WHITE

Starter Motor

BLACK

MIL

RED

Oil

Pressure

Switch

BLACK GREY

10A

1018

RED/BLACK

DARK BLUE

A B A B A B C DA B C 1 2 31 2A B C A B1 2

DARK GREEN

RED/BLACK

BLACK

RED/BLACK

PURPLE

Fuse

YELLOW

DARK GREEN

RED/BLACK

PURPLE

BLACK

GREY

BLACK

DARK BLUE

31 2

10A

Fuse

GREY

LIGHT GREEN

BLACK

DARK GREEN

BLACK

TAN

WHITE

BLACK

1 2

RED/BLACK

DARK BLUE

Fuel

Injector

Fuel

Injector

Ignition

Coil

Ignition

Coil

Crankshaft

Position

Sensor

Oxygen

Sensor

Throttle

Position

Sensor

Manifold Absolute Pressure

Sensor

Oil

Temperature

Sensor

Intake

Air

Temperature

Sensor

Diagnostic Connector

5-Terminal Engine Mounted Key Switch

DARK BLUE

Accessory

5-Terminal

RectifierRegulator

BLACK

Battery

PURPLE

Stator

30A

1018

Fuse

RED

PINK

RED/BLACK

1 2

Fuel Pump

RED/BLACK

YELLOW

10A

WHITE

Fuse

E D

Connector

YELLOW

TAN

Key Switch

MIL

RED

DARK GREEN

Starter Motor

Oil

Pressure

Switch

BLACK GREY

BLACK

10A

1018

RED/BLACK

DARK BLUE

DARK GREEN

RED/BLACK

BLACK

RED/BLACK

PURPLE

Fuse

YELLOW

PURPLE

DARK GREEN

RED/BLACK

PURPLE

BLACK

GREY

BLACK

DARK BLUE

GREY

LIGHT GREEN

BLACK

DARK GREEN

BLACK

TAN

BLACK

WHITE

BLACK

1 2

RED/BLACK

DARK BLUE

A B A B A B C DA B C 1 2 31 2A B C A B1 2

Fuel

Injector

Fuel

Injector

Ignition

Coil

Ignition

Coil

Crankshaft

Position

Sensor

Oxygen

Sensor

Throttle

Position

Sensor

31 2

Manifold Absolute Pressure

Sensor

Oil

Temperature

Sensor

Intake

Air

Temperature

Sensor

Diagnostic Connector

Section 5

EFI Fuel System

Crankshaft Position Sensor

Figure 5-3. Crankshaft Position Sensor.

General

The cranksha position sensor is essential to engine operation; constantly monitoring the rotation and speed (RPM) of the cranksha . There are 23 consecutive teeth cast into the ﬂ ywheel. One tooth is missing and is used to reference the cranksha position for the ECU. The inductive cranksha position sensor is mounted

0.20-0.70 mm (0.008-0.027 in.) from the ﬂ ywheel.

During rotation, an AC voltage pulse is created within the sensor for each passing tooth. The ECU calculates engine speed from the time interval between the consecutive pulses. The gap from the missing tooth creates an interrupted input signal, corresponding to speciﬁ c cranksha position near BDC for cylinder #1. This signal serves as a reference for the control of ignition timing by the ECU. Synchronization of the inductive speed pickup and cranksha position takes place during the ﬁ rst two revolutions each time the engine is started. The sensor must be properly connected at all times. If the sensor becomes disconnected for any reason, the engine will quit running.

4. Disconnect the Black connector from the ECU.

5. Connect an ohmmeter between the #4 and #13 pin

terminals. A resistance value of 325-395  at room temperature (20°C, 68°F) should be obtained. If resistance is correct, check the mounting, air gap,

ﬂ ywheel teeth (damage, run-out, etc.), and ﬂ ywheel key.

6. Disconnect the cranksha position sensor connector from the wiring harness. Test resistance between the terminals. A reading of 325-395  should again be obtained.

a. If the resistance is incorrect, remove the

screws securing the sensor to the mounting bracket and replace the sensor.

b. If the resistance in step 5 was incorrect, but

the resistance of the sensor alone was correct, test the wire harness circuits between the sensor connector terminals and the corresponding pin terminals (#4 and #13) in the main connector. Correct any observed problem, reconnect the sensor, and perform step 5 again.

7. When fault is corrected and engine starts, clear fault codes following the ECU Reset procedure. See page 5.11.

Throttle Position Sensor (TPS)

Pin A

Pin C Pin B

Service

The cranksha position sensor is a sealed, non- serviceable assembly. If Fault Code diagnosis indicates a problem within this area, test and correct as follows.

1. Check the mounting and air gap of the sensor. It

must be 0.20-0.70 mm (0.008-0.027 in.).

2. Inspect the wiring and connections for damage or problems.

3. Make sure the engine has resistor type spark plugs.

Figure 5-4. Throttle Position Sensor with Pinout.

General

The thro le position sensor (TPS) is used to indicate thro le plate angle to the ECU. Since the thro le (by way of the governor) reacts to engine load, the angle of the thro le plate is directly related to the load on the engine.

5.9

Section 5 EFI Fuel System

Mounted on the thro le body and operated directly oﬀ the end of the thro le sha , the TPS works as a potentiometer, varying the voltage signal to the ECU in direct correlation to the angle of the thro le plate. This signal, along with the other sensor signals, is processed by the ECU and compared to the internal preprogrammed maps to determine the required fuel and ignition se ings for the amount of load.

The correct position of the TPS is established and set at the factory. Do not loosen the TPS or alter the mounting position unless absolutely required by fault

code diagnosis. If the TPS is loosened or repositioned,

the appropriate TPS Learn Procedure must be performed to re-establish the baseline relationship between the ECU and the TPS.

4. Leave the leads connected to the pin terminals as described in step 3. Rotate the thro le sha slowly to the full thro le position. Monitor the dial during rotation for indication of any momentary short or open circuits. Note the resistance at the full thro le position. It should be 4600-5200 without a stop pin, or 3200-4100 Ω with a stop pin.

5. Disconnect the main wiring harness connector from the TPS, leaving the TPS assembled to the thro le body. Refer to the following chart and perform the resistance checks indicated between the terminals in the TPS switch, with the thro le in the positions speciﬁ ed. Pin location shown in Figure 5-4.

Thro le Position

Closed A & C 1400-1800 Yes

Full with Stop

Full without

Stop Pin

Any A & B 3000-7000 Yes

Between

Terminal

A & C 3200-4100 Yes

A & C 4600-5200 Yes

Resistance

Value (Ω)

Continuity

Figure 5-5. TPS Location.

Service

The TPS is a sealed, non-serviceable assembly. If diagnosis indicates a bad sensor, complete replacement is necessary. If a blink code indicates a problem with the TPS, it can be tested as follows:

1. Counting the number of turns, back out the idle speed adjusting screw (counterclockwise) until the thro le plates can be closed completely. Write this number down for reference later.

2. Disconnect the Black connector from the ECU, but leave the TPS mounted to the thro le body.

3. a. Use an ohmmeter and connect the red

(positive) ohmmeter lead to Black pin 12 terminal and the black (negative) ohmmeter lead to Black pin 10 terminal to test.

b. Hold the thro le closed and check the

resistance. It should be 1400-1800 Ω.

If the resistance values in steps 3, 4, and 5 are

within speciﬁ cations, go to step 6.

If the resistance values are not within

speciﬁ cations, or a momentary short or open circuit was detected during rotation (step 4), the TPS needs to be replaced, go to step 7.

6. Check the TPS circuits (input, ground) between the TPS plug and the main harness connector for continuity, damage, etc. The input pin is 12 and the ground is pin 10.

a. Repair or replace as required.

b. Turn the idle speed screw back in to its

original se ing.

c. Reconnect connector plugs, start engine and

retest system operation.

7. Remove the two mounting screws from the TPS. Save the screws for reuse. Remove and discard the faulty TPS. Install the replacement TPS and secure with the original mounting screws.

a. Reconnect the Black and TPS connector plugs.

5.10

b. Perform the TPS Learn Procedure integrating

the new sensor to the ECU.

Section 5

EFI Fuel System

ECU Reset and TPS Learn Procedure

Any service to the ECU, TPS/Thro le Body (including idle speed increase over 300 RPM), or the fuel pump module should include ECU Reset.

This will clear all trouble codes, all closed loop learned oﬀ sets, all max values, and all timers besides the permanent hour meter.

The system will NOT reset when the ba ery is disconnected!

ECU Reset Procedure

1. Turn key OFF.

2. Install Red wire jumper (Figure 5-6) from Kohler EFI service kit on to service port (connect the white wire to the black wire in the 4 way diagnostic port).

4. Adjust idle speed down to 1500 RPM. Allow engine to dwell at 1500 RPM for about 3 seconds.

5. A er this, adjust the idle speed to the ﬁ nal speciﬁ ed speed se ing.

6. Turn the key OFF and count to 10 seconds.

Learn is complete and the engine is ready for operation.

Engine (Oil) Temperature Sensor

Pin 1

Figure 5-6. Service Port and Jumper Connector.

3. Turn key ON, then OFF and count 10 seconds.

4. Turn key ON, then OFF and count to 10 seconds a second time.

5. Remove the jumper, ECU is reset. A TPS Learn Procedure must be performed a er the ECU Reset.

TPS Learn Procedure

1. Turn idle screw clockwise one full turn prior to key ON a er ECU Reset.

2. Start engine, run at low idle until engine is warm.

3. Idle speed must be above 1500 RPM. If below 1500 RPM, turn idle screw up to 1700 RPM and then shut down engine and perform ECU Reset again.

Pin 2

Figure 5-7. Engine (Oil) Temperature Sensor.

General

The engine (oil) temperature sensor (Figure 5-7) is used by the system to help determine fuel requirements for starting (a cold engine needs more fuel than one at or near operating temperature).

Mounted in the breather cover, it has a temperaturesensitive resistor that extends into the oil ﬂ ow. The resistance changes with oil temperature, altering the voltage sent to the ECU. Using a table stored in its memory, the ECU correlates the voltage drop to a speciﬁ c temperature. Using the fuel delivery maps, the ECU then knows how much fuel is required for starting at that temperature.

Service

The temperature sensor is a sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem with the temperature sensor, it can be tested as follows:

1. Remove the temperature sensor from the breather cover and cap or block the sensor hole.

2. Wipe the sensor clean and allow it to reach room temperature (25°C, 77°F).

5.11

Section 5 EFI Fuel System

3. Unplug the Black connector from the ECU.

4. With the sensor still connected, check the temperature sensor circuit resistance between the Black pin 10 and 14 terminals. The value should be 9000-11000 .

5. Unplug the sensor from the wire harness and check the sensor resistance separately across the two pins. Resistance value should again be 9000-11000 .

a. If the resistance is out of speciﬁ cations,

replace the temperature sensor.

b. If it is within speciﬁ cations, proceed to Step 6.

6. Check the circuits (input, ground), from the wire harness connector to the sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 14 in the wire harness connector (as in step 4). Connect the other lead to terminal #1 in the sensor plug (see Figure 5-7). Continuity should be indicated. Repeat the test between Black pin 10 and terminal #2 in the sensor plug.

Intake Air Temperature Sensor

The purpose of an air temperature sensor is to help the ECU calculate air density. The higher the air temperature gets the less dense the air becomes. As the air becomes less dense the ECU knows that it needs to lessen the fuel ﬂ ow to achieve the correct air/fuel ratio. If the fuel ratio was not changed the engine would become rich, possibly losing power and consuming more fuel.

Service

The intake air temperature sensor is a non-serviceable component. Complete replacement is required if it is faulty. The sensor and wiring harness can be checked as follows.

1. Remove the temperature sensor from the thro le body.

2. Allow it to reach room temperature (20°C, 68°F).

3. Unplug the Black connector from the ECU.

4. With the sensor still connected, check the temperature sensor circuit resistance between the Black pin 10 and 8 pin terminals. The value should be 3100-3900 .

5. Unplug the sensor from the wire harness and check the sensor resistance separately across the two pins. Resistance value should again be 3100-3900 .

Pin 2

Pin 1

Figure 5-8. Intake Air Temperature Sensor.

General

The Intake Air Temperature (IAT) sensor is a thermally sensitive resistor that exhibits a change in electrical resistance with a change in its temperature.

When the sensor is cold, the resistance of the sensor is high, and the voltage signal is high. As the sensor warms up, the resistance drops and voltage signal decreases. From the voltage signal, the ECU can determine the temperature of the intake air.

a. If the resistance is out of speciﬁ cations, replace

the temperature sensor.

b. If it is within speciﬁ cations, proceed to Step 6.

6. Check the circuits (input, ground), from the main harness connector to the sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 8 in the main harness connector (as in step 4). Connect the other lead to terminal #1 in the sensor plug (see Figure 5-8). Continuity should be indicated. Repeat the test between Black pin 10 and terminal #2 in the sensor plug.

5.12

Section 5

EFI Fuel System

Oxygen Sensor

Pin A

Pin D

Figure 5-9. Oxygen Sensor.

General

The oxygen sensor functions like a small ba ery, generating a voltage signal to the ECU based upon the diﬀ erence in oxygen content between the exhaust gas and the ambient air.

The tip of the sensor, protruding into the exhaust gas, is hollow (see cutaway Figure 5-10). The outer portion of the tip is surrounded by the exhaust gas, with the inner portion exposed to the ambient air. When the oxygen concentration on one side of the tip is diﬀ erent than that of the other side, a voltage signal up to 1.0 volt is generated and sent to the ECU. The voltage signal tells the ECU if the engine is straying from the ideal fuel mixture, and the ECU then adjusts the injector pulse accordingly.

The oxygen sensor functions a er being heated to a minimum of 400°C (752°F). A heater inside the sensor heats the electrode to the optimum temperature in about 10 seconds. The oxygen sensor receives the ground through the wire, eliminating the need for proper grounding through the muﬄ er. If problems indicate a bad oxygen sensor, check all connections and wire harness. The oxygen sensor can also be contaminated by leaded fuel, certain RTV and/or other silicone compounds, fuel injector cleaners, etc. Use only those products indicated as O2 Sensor Safe.

Pin B Pin C

Service

The temperature must be controlled very accurately and gas constituents measured to a high degree of accuracy for absolute sensor measurements. Since this requires laboratory equipment, it is not possible to distinguish a marginally in speciﬁ cation sensor from a marginally out of speciﬁ cation sensor with simple ﬁ eld diagnostic equipment. Furthermore, as with most devices, intermi ent problems are diﬃ cult to diagnose. Still, with a good understanding of the system and the sensor, it is possible to diagnose many sensor problems in the ﬁ eld.

12 345 6

1. Protection Shield

2. Planar Element and Heater

3. Lower Insulator

4. Stainless Steel Housing

Figure 5-10. Cutaway of Oxygen Sensor.

Using diagnostic so ware connected to the ECU is a useful technique for observing sensor performance. However, the user must understand that such so ware reads a signal generated by the ECU. If there is an ECU or wiring problem, the readings could be misinterpreted as a sensor problem. The digital nature of the signal to the so ware means that it is not reading the continuous output of the sensor. A voltmeter can also be used as an eﬀ ective tool in diagnosing sensors. It is advisable to use an electronic meter such as a digital voltmeter. Simple mechanical meters may place a heavy electrical load on the sensor and cause inaccurate readings. Since the resistance of the sensor is highest at low temperatures, such meters will cause the largest inaccuracies when the sensor is in a cool exhaust.

5. Upper Insulator

6. Terminal Connection to Element

7. High Temp Water Seal

5.13

Section 5 EFI Fuel System

Visual Inspection

1. Look for a damaged or disconnected sensor-toengine harness connection.

2. Look for damage to the sensor lead wire or the associated engine wiring due to cu ing, chaﬃ ng or melting on a hot surface.

3. Disconnect the sensor connector and look for corrosion in the connector.

4. Try reconnecting the sensor and observe if the problem has cleared.

5. Correct any problems found during the visual check.

Sensor Signal Observation

If the visual examination shows no problems, connect the sensor back to the engine harness.

NOTE: Do not cut into or pierce the sensor or engine

wiring to make this connection. The sensor produces a very small signal. Corrosion or damage to the wiring could lead to an incorrect signal because of repairs or contamination to the sensor.

1. Using a voltmeter or diagnostic so ware observe the voltage before the engine is started. With the key ON, the voltage should read about 1.0 volt. This voltage is generated by the ECU. If it is not present, disconnect the sensor and observe the voltage at the harness connector. If the voltage is now present, there is a short in the sensor or associated wiring and corrective action should be taken. If the voltage still is not present, there is a problem with the ECU or engine harness.

2. Reconnect the sensor and start the engine. Run the engine at suﬃ cient speed to bring the sensor up to operating temperature. Maintain for 1 to 2 minutes to ensure that the engine has gone closed loop. Once in closed loop, the sensor voltage should cycle between about 100 to 250 mv and 700 to 900 mv. If this cycling is not observed, a determination must be made. If the problem is with the engine or the sensor.

NOTE: Using the diagnostic so ware, the wiring and

ECU integrity can be checked by grounding the signal wire; the output of the sensor, read on the so ware, should be around 4 mv.

Removal Inspection

1. If the sensor has heavy deposits on the lower shield, the engine, oil, or fuel may be the source.

2. If heavy carbon deposits are observed, incorrect engine fuel control may be occurring.

3. If the sensor is at room temperature, measure between the signal leads, the black wire (Pin C) and grey wire (Pin D) a ached to the sensor (see Figure 5-9). If the resistance is less than one megohm, the sensor has an internal short.

4. With the sensor at room temperature measure the heater circuit resistance, purple wire (Pin A) and white wire (Pin B), resistance should be

8.1-11.1 Ω.

5. If a damaged sensor is found, identify the root cause, which may be elsewhere in the application. The table on the following page summarizes sensor symptoms and corrections. It includes items, which apply to both diagnostics and application system design.

6. A special "dry to touch" anti-seize compound is applied to all new oxygen sensors at the factory. If the recommended mounting thread sizes are used, this material provides excellent anti-seize capabilities and no additional anti-seize is needed. If the sensor is removed from the engine and reinstalled, the anti-seize compound should be reapplied. Use a oxygen sensor safe type anti-seize compound. It should be applied according to the directions on the label.

NOTE: Apply the anti-seize compound only to the

threads. Anti-seize compound will aﬀ ect sensor performance if it gets into the lower shield of the sensor.

3. Check engine harness for ba ery voltage on the heater circuit.

5.14

Section 5

EFI Fuel System

Oxygen Sensor Symptoms and Corrections

CONDITION POSSIBLE CAUSE CORRECTION

Low voltage output Shorted sensor or sensor circuit Replace sensor or repair wiring

Shorted lead wire

Wiring shorted to ground

Remove source of external

Contamination of air reference

Air leak at sensor or gasket, sensor upper shield damage

contamination, protect air reference area

Use recommended torque at installation, replace gasket or sensor

Revise application exhaust

Shield sensor from damage

High voltage output Silica poisoning Replace sensor

Contaminated gasoline Use high quality fuel

Engine problem; misﬁ re Correct cause of misﬁ re

Excessive rich air/fuel ratio Correct air/fuel ratio

Wiring shorted to voltage Repair wiring

Open circuit, no activity from sensor

Slow time response Open heater circuit Replace sensor

Broken element Replace sensor

Sensor dropped

Hard blow to engine or exhaust system

Defective sensor

Thermal shock

Improper handling

Carbon deposits

Improper fueling Correct fueling

Incorrect or contaminated fuel Use high quality fuel

Excessive engine oil consumption causing exhaust contamination or other exhaust side contamination

Heater circuit open/shorted or out of speciﬁ cation

Correct engine condition

Repair short in harness wires, replace sensor

5.15

Section 5 EFI Fuel System

Manifold Absolute Pressure Sensor

Locking Tab

Pin 1

Figure 5-11. Manifold Absolute Pressure Sensor and Connector.

General

The manifold absolute pressure (MAP) sensor provides immediate manifold pressure information to the ECU. The MAP measures the diﬀ erence in pressure between the outside atmosphere and the vacuum level inside the intake manifold and monitors pressure in the manifold as the primary means of detecting load. The data is used to calculate air density and determine the engine's mass air ﬂ ow rate, which in turn determines the required ideal fueling. The MAP also stores instant barometric pressure reading when the key is turned ON.

Service

The manifold absolute pressure sensor is a sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem with the manifold absolute pressure sensor, it can be tested as follows:

1. Make sure all connections are making proper contact and are free of dirt and debris. Remove the blower housing. Slide the locking tab out and pull oﬀ the manifold absolute pressure connector. Turn the key switch to ON and check with a volt meter by contacting the red lead to pin 1 and the black lead to pin 2. See Figure 5-11 for pin location. There should be 5 volts present, indicating the ECU and wiring harness are functioning.

2. Check continuity in wire harness. Ohms between Pin 3 at the sensor connector and Black pin 11 connector at ECU should be near zero ohms. If no continuity is measured or very high resistance, replace wire harness.

Pin 3

Pin 2

3. Check to make sure the intake manifold is not loose and the MAP sensor is not loose. Loose parts would allow a vacuum leak, making the MAP sensor report misleading information to the ECU.

a. Tighten all hardware and perform an ECU

Reset and a TPS Learn Procedure to see if the MIL will display a fault with the MAP sensor again. If the MIL ﬁ nds a fault with the MAP sensor, replace it.

Fuel Injectors

Figure 5-12. Fuel Injector.

General

The fuel injectors mount into the intake manifold, and the high pressure fuel line a aches to them at the top end. Replaceable O-rings on both ends of the injector prevent external fuel leakage and also insulate it from heat and vibration. A special clip connects each injector to the high pressure fuel line and holds it in place. The O-rings and retaining clip should be replaced any time the fuel injector is separated from its normal mounting position. DO NOT reuse existing O-rings or retaining clips as fuel leakage may result.

When the key switch is on, the fuel pump module will pressurize the high pressure fuel line to 39 psi, and voltage is present at the injector. At the proper instant, the ECU completes the ground circuit, energizing the injector. The valve needle in the injector is opened electromagnetically, and the pressure in the high pressure fuel line forces fuel down through the inside. The director plate at the tip of the injector contains a series of calibrated openings which directs the fuel into the manifold in a cone-shaped spray pa ern.

5.16

Section 5

EFI Fuel System

The injectors have sequential fueling that open and close once every other cranksha revolution. The amount of fuel injected is controlled by the ECU and determined by the length of time the valve needle is held open, also referred to as the injection duration or pulse width. The time the injector is open (milliseconds) may vary in duration depending on the speed and load requirements of the engine.

6 8

1. Electrical Connection

2. Upper O-ring

3. Solenoid Winding

4. Armature

5. Valve Housing

Figure 5-13. Fuel Injector Details.

Service

Injector problems typically fall into three general categories: electrical, dirty/clogged, or leakage. An electrical problem usually causes one or both of the injectors to stop functioning. Several methods may be used to check if the injectors are operating.

1. With the engine running at idle, listen for a buzzing or clicking sound.

2. Disconnect the electrical connector from an injector and listen for a change in idle performance (only running on one cylinder) or a change in injector noise or vibration.

6. Valve Seat

7. Valve End

8. Lower O-ring

9. Director Plate

7 9

NOTE: Do not apply voltage to the fuel injector(s).

Excessive voltage will burn out the injector(s). Do not ground the injector(s) with the ignition ON. Injector(s) will open/turn on if relay is energized.

1. Disconnect the electrical connector from both injectors. Plug a 12 volt noid light (part of EFI Service Kit, see Section 2) into one connector.

Figure 5-14. Volt Noid Light.

2. Make sure all safety switch requirements are met. Crank the engine and check for ﬂ ashing of the test light. Turn key OFF for at least 10 seconds between tests to allow ECU to go to sleep and reawake. Repeat test at other connector.

NOTE: When cranking engine with injectors

disconnected, fault codes will be registered in the ECU and will need to be cleared using so ware fault clear or an ECU Reset and TPS Learn Procedure.

a. If ﬂ ashing occurs, use an ohmmeter (Rx1

scale) and check the resistance of each injector across the two terminals. Proper resistance is 11-13 . If injector resistance is correct, check whether the connector and injector terminals are making a good connection. If the resistance is not correct, replace the injector.

Check all electrical connections, connectors, and wiring harness leads if resistance is incorrect.

If an injector is not operating, it can indicate either a bad injector, or a wiring/electrical connection problem. Check as follows:

5.17

Section 5 EFI Fuel System

Injector leakage is very unlikely, but in those rare instances it can be internal (past the tip of the valve needle), or external (weeping around the injector O-rings). See Figure 5-15. The loss of system pressure from the leakage can cause hot restart problems and longer cranking times. To check for leakage it will be necessary to loosen or remove the blower housing which may involve removing the engine from the unit.

Check for Leaks

Figure 5-15. Injector Inspection Points.

1. Engine must be cool. Depressurize fuel system as stated on page 5.2.

2. Disconnect spark plug leads from spark plugs.

3. Remove the air cleaner by removing the two top screws and the three nuts securing the air cleaner base to the thro le body. Service air cleaner components as required.

4. Remove the ﬂ ywheel grass screen if it overlaps the blower housing.

5. Remove the two oil cooler mounting screws.

6. Remove the two screws for the pulse pump.

11. Disconnect the breather tube on top of the thro le body.

12. Disconnect the vent hose underneath the thro le body.

13. Disconnect the rectiﬁ er-regulator connector.

14. Remove the blower housing mounting screws. Note the location of the plated (silver) screw a aching the rectiﬁ er-regulator ground bracket. To gain access to the screw behind the dipstick tube, remove the dipstick tube screw and pull the tube out. Remove the blower housing.

15. Thoroughly clean the area around and including the thro le body/manifold and the injectors.

16. Disconnect the thro le linkage and linkage spring from the governor lever. Disconnect the TPS lead from the harness.

17. Remove the manifold mounting bolts and separate the thro le body/manifold from the engine leaving the TPS, high pressure fuel line, injectors and fuel line connections intact. Discard the old gaskets.

18. Position the manifold assembly over an appropriate container to capture fuel and turn the key switch ON to activate the fuel pump and pressurize the system. Do not turn switch to START position.

19. If either injector exhibits leakage of more than two to four drops per minute from the tip, or shows any sign of leakage around the outer shell, turn the ignition switch OFF and replace the injector as follows.

20. Depressurize the fuel system following the procedure in the fuel warning on page 5.2.

7. Remove the fuse bracket if equipped.

8. Remove one screw securing the ECU bracket into the blower housing.

9. Remove the top nut, washer and spring for the thro le control sha and the two screws for the thro le control bracket.

10. Remove oil separator mounting hardware if equipped.

5.18

21. Clean any dirt accumulation from the sealing/ mounting area of the faulty injector(s) and disconnect the electrical connector(s).

22. Pull the retaining clip oﬀ the top of the injector(s). Remove the screw holding the injector(s) from the manifold.

Section 5

EFI Fuel System

23. Reverse the appropriate procedures to install the new injector(s) and reassemble the engine. Use new O-rings and retaining clips any time an injector is removed (new replacement injectors include new O-rings and retaining clips). Lubricate O-rings lightly with clean engine oil. Use the installation tool provided with the O-rings to install the new upper O-ring. Place the tool into the fuel injector inlet. Place one side of the O-ring into the O-ring groove and roll the O-ring over the tool onto the fuel injector. Torque the screw securing the fuel injector caps and blower housing mounting screws to 7.3 N·m (65 in. lb.), and the intake manifold and air cleaner mounting screws to 10.5 N·m (93 in. lb.). An ECU Reset will need to be completed. Follow the instructions on page 5.11.

Injector problems due to dirt or clogging are generally unlikely due to the design of the injectors, the high fuel pressure, and the detergent additives in the gasoline. Symptoms that could be caused by dirty/ clogged injectors include rough idle, hesitation/ stumbling during acceleration, or triggering of fault codes related to fuel delivery. Injector clogging is usually caused by a buildup of deposits on the director plate, restricting the ﬂ ow of fuel, resulting in a poor spray pa ern. Some contributing factors to injector clogging include higher than normal operating temperatures, short operating intervals, and dirty, incorrect, or poor quality fuel. Cleaning of clogged injectors is not recommended; they should be replaced. Additives and higher grades of fuel can be used as a preventative measure if clogging has been a problem.

General

A high-voltage, solid-state, ba ery ignition system is used with the EFI system. The ECU controls the ignition output and timing through transistorized control of the primary current delivered to the coils. Based on input from the cranksha position sensor, the ECU determines the correct ﬁ ring point for the speed at which the engine is running. At the proper instant, it interrupts the ﬂ ow of primary current in the coil, causing the electromagnetic ﬂ ux ﬁ eld to collapse. The ﬂ ux collapse induces an instantaneous high voltage in the coil secondary which is strong enough to bridge the gap on the spark plug. Each coil ﬁ res every other revolution.

Service

If a coil is determined to be faulty, replacement is necessary. An ohmmeter may be used to test the wiring and coil windings.

NOTE: Do not ground the coils with the ignition ON

as they may overheat or spark.

NOTE: Always disconnect the spark plug lead

from the spark plug before performing the following tests.

Testing

1. Using an ohmmeter set on the Rx1 scale, check the resistance in circuits as follows:

a. Disconnect the Black connector from the ECU

to check the number one cylinder coil (starter side). Test between Black pin 1 and Black pin

15.

Ignition System

Figure 5-16. Ignition Coil.

b. Disconnect the Grey connector from the ECU

to check the number two cylinder coil (oil ﬁ lter side). Test between Grey pin 10 and Grey pin 17. A reading of 0.5-0.8  in each test indicates that the wiring and coil primary circuits are OK.

c. If reading(s) are not within speciﬁ ed range,

check and clean connections and retest.

d. If reading(s) are still not within the speciﬁ ed

range, test the coils separately from main harness as follows:

1) Remove the screw retaining the coil to the

housing and disconnect the primary leads connector.

5.19

Section 5 EFI Fuel System

2) Connect an ohmmeter set on the Rx1 scale to the primary terminals of the coil. Primary resistance should be 0.5-0.8 .

3) Connect an ohmmeter set on the Rx10K scale between the spark plug boot terminal and the B+ primary terminal. Secondary resistance should be 6400-7800 .

4) If the secondary resistance is not within the speciﬁ ed range, the coil is faulty and needs to be replaced.

NOTE: If the ignition coil(s) are disabled and an

ignition fault is registered, the system will automatically disable the corresponding fuel injector drive signal. The fault must be corrected to the ignition coil and the ECU power (switch) must be turned OFF for 10 seconds for the injector signal to return. This is a safety measure to prevent bore washing and oil dilution.

Spark Plugs

EFI engines are equipped with Champion® RC12YC resistor spark plugs. Equivalent alternate brand plugs can also be used, but must be resistor plugs or permanent damage to the ECU will occur, in addition to aﬀ ecting operation. Proper spark plug gap is

0.76 mm (0.030 in.).

Fuel Components

Fuel Pump

General

An electric fuel pump module and a li pump (two types) are used to transfer fuel in the EFI system. See Figures 5-17 and 5-18. The two types of li pumps are a pulse fuel pump and a mechanical fuel pump. The pumping action is created by either the oscillation of positive and negative pressures within the crankcase through a hose, or by direct lever/pump actuation oﬀ rocker arm movement. The pumping action causes the diaphragm on the inside of the pump to pull fuel in on its downward stroke and to push it into the fuel pump module on its upward stroke. Internal check valves prevent fuel from going backward through the pump. The fuel pump module receives the fuel from the li pump, increases and regulates the pressure for the fuel injectors.

Battery Charging System

EFI engines are equipped with either a 20 or 25 amp charging system to accommodate the combined electrical demands of the ignition system and the speciﬁ c application. Charging system troubleshooting information is provided in Section 7.

Figure 5-17. Fuel Pump Module.

5.20

Section 5

EFI Fuel System

Service

The fuel pump module is not serviceable and must be replaced if determined to be faulty. If a fuel pump problem is suspected, make certain the pump is being activated, all electrical connections are properly secured, the fuses are good, and a minimum of 7.0 volts is being supplied. If during cranking, voltage drops below 7.0 volts, a reduction of fuel pressure may occur resulting in a lean starting condition. If required, testing of the fuel pump may be conducted.

1. Relieve fuel pressure at the fuel pump module following the instructions on page 5.2. The fuel pump module may need to be loosened or pulled away from the engine. Disconnect the fuel coupler from the fuel pump module and insert the pressure test jumper (from Kohler EFI Service Kit) between the high pressure fuel line and the fuel pump module.

2. Connect the black hose of Pressure Tester (part of EFI Service Kit, see Section 2). Route the clear hose into a portable gasoline container or the equipment fuel tank.

Figure 5-18. Pulse and Mechanical Fuel Pump.

The fuel pump module is rated for a minimum output of 13.5 liters per hour and regulated at 270 kilo pascals (39 psi).

When the key switch is turned ON and all safety switch requirements are met, the ECU activates the fuel pump module for about six seconds, which pressurizes the system for start-up. If the key switch is not promptly turned to the start position, the engine fails to start, or the engine is stopped with the key switch ON (as in the case of an accident), the ECU switches oﬀ the pump preventing the continued delivery of fuel. In this situation, the MIL will go on, but it will go back oﬀ a er 4 cranking revolutions if system function is OK. Once the engine is running, the fuel pump remains on.

3. Turn on the key switch to activate the pump and check the system pressure on the gauge. It may take several key cycles to compress the air introduced into the system and reach regulated pressure. If system pressure of 39 psi ± 3 is observed, the wiring, fuel pump, and regulator are working properly. Turn key switch OFF and depress the valve bu on on the tester to relieve the system pressure.

a. If the pressure is too high, replace the fuel

pump module.

b. If the pressure is too low, replace the fuel

pump module.

4. If the pump did not activate (step 3), disconnect the plug from the fuel pump. Connect a DC voltmeter across the terminals in the plug, turn on the key switch and observe if a minimum of 7 volts is present during the six second prime process.

5. If no voltage is observed, connect the red lead of meter to the red wire of the plug and the black lead to a good ground while the key is still ON.

5.21

Section 5 EFI Fuel System

6. If voltage is between 7 and 14, turn key switch OFF and connect an ohmmeter between the terminals on the pump to check for continuity.

a. If there was no continuity between the pump

terminals, replace the fuel pump.

b. If the voltage was below 7, test the wiring

harness.

7. If voltage at the plug was good, and there was continuity across the pump terminals, reconnect the plug to the pump, making sure you have a good connection. Turn on the key switch and listen for the pump to activate.

a. If the pump starts, repeat steps 2 and 3 to

verify correct pressure.

b. If the pump still does not operate, replace it.

NOTE: The fuel pump module pins are coated with

a thin layer of electrical grease to prevent

freingandcorrosion.Donotaemptto

remove electrical grease from the fuel pump module pins.

Iftherearetwoltersinthesystem,theonebefore thelipumpwillbeastandard51-75micronlter, andtheoneaerthelipumpwillbethespecial 10-micronlter.Besuretouseanapproved10-micron lterforreplacement.

Service

Periodicallyinspectthelterandreplaceevery 200 operating hours or more frequently under extremely

dusty or dirty conditions. Use only a genuine Kohler

lterandinstallitaccordingtothedirectionalarrows. Failuretousetheproperltercanresultinengine

damage and void the warranty.

High Pressure Fuel Line

Fuel Filter

Figure 5-19. In-Line Fuel Filter.

General

The precision components inside the fuel pump

modulearenotserviceable.DONOTaempttoopen

the fuel pump module. Damage to the components will result and the warranty will be void. Because the fuel pump module is not serviceable, the engines

areequippedwithaspecial10-micronEFIfuellter

to prevent harmful contamination from entering the module. See Figure 5-19.

Figure 5-20. High Pressure Fuel Line with Fuel Injectors.

General

The high pressure fuel line is an assembly of hoses, injector caps and a fuel connector to the fuel pump module. The high pressure fuel line feeds fuel to the top of the injectors through the injector caps. The caps are fastened to the intake manifold and the injectors are locked into place. A small retaining clip provides a secondary lock.

The high pressure fuel line is serviced as a complete assembly to prevent tampering and safety hazards. The components are not individually serviceable.

These engines use low permeation rated fuel lines,

certiedtocomplywithCaliforniaandU.S.EPA

evaporative emission requirements. Fuel lines that do not meet these requirements may not be used. Order replacement hose through a Kohler Service Center.

CAUTION:

Low permeation high-pressure fuel line with an SAE 30R9 or 30R12 rating (1/4 in. I.D.) is required for safe and

reliable operation due to higher operating pressure of the EFI system. Low permeation low-pressure fuel line with a

SAE 30R7 rating (1/4 in. I.D.) may only be used between the fuel tank and li pump, between the li pump and fuel pump module, or as otherwise congured in the application.

5.22

Section 5

EFI Fuel System

Service

The high pressure fuel line is mounted to the

intakemanifold.Nospecicservicingisrequired

unless operating conditions indicate that it needs replacement. It can be detached by removing the two mounting screws, wire ties, and the injector retaining clips. Thoroughly clean the area around all joints and relieve any pressure before starting any disassembly by following the instruction on page 5.2.

Purge Port and Vent Hose Assembly

Purge Port

Figure 5-21. Purge Port Location.

Throttle Body/Intake Manifold Assembly

Figure 5-22. Throttle Body/Intake Manifold Details.

General

TheEFIengineshavenocarburetor,sothethrole function(regulateincomingcombustionairow)is achievedwithathrolevalveinaseparatethrole bodyaachedtotheintakemanifold.Thethrole

body/intake manifold provides mounting for the

fuelinjectors,throlepositionsensor,intakeair

temperature sensor, high pressure fuel line, idle speed screw, and air cleaner assembly. See Figure 5-22.

General

The vent hose assembly is intended to vent fuel vapor out of the fuel pump module and direct the fuel vapor

intothethrolebody.AllEFIenginesareequipped

with an engine mounted purge port on the #2 cylinder

barrelbae.Thiscappedpurgeportcanbeusedby

the OEM to vent fuel tanks or used in conjunction with a carbon canister kit for Tier III evaporative emissions compliance. The purge port connects to the vent hose assembly and directs all fuel vapor into

thethrolebody.Ifthepurgeportremainsunused,

the port must remain capped to prevent dirt from entering the engine. See Figure 5-21.

Service

Nospecicservicingisrequiredfortheventhose

assembly or purge port unless operating conditions indicate replacement is required. All components are serviced individually. Abrasion sleeves on hoses should be reused or replaced when servicing vent hoses. Please note vent hose routing and replicate

aerserviceorcomponentreplacementtoprevent

pinching or abrasion of the vent hoses.

Service

Thethrolebodyisservicedasanassembly,with thethrolesha,TPS,throleplate,andidlespeed adjustingscrewinstalled.Thethrolesharotateson

needle bearings (non-serviceable), capped with seals to prevent air leaks.

NOTE: ECUResetisrequiredifthethrolebodyis

replaced.

Idle Speed Adjustment (RPM)

Idle Speed Adjustment Screw

Figure 5-23. Idle Speed Adjustment.

5.23

Section 5

High-Speed Throttle Stop Pin

Linkage Bushing

Throttle Linkage

Damper Spring

EFI Fuel System

General

The idle speed is the only adjustment that may be performed on the EFI system. The standard idle speed se ing for EFI engines is 1500 RPM, but certain applications might require a diﬀ erent se ing. Check the equipment manufacturer’s recommendation.

For starting and warm up, the ECU will adjust the fuel and ignition timing, based upon ambient temperature, engine temperature, and loads present. In cold conditions, the idle speed will probably be diﬀ erent than normal for a few moments. Under other conditions, the idle speed may actually start lower than normal, but gradually increase to the established se ing as operation continues. Do not a empt to circumvent this warm up period, or readjust the idle speed during this time. The engine must be completely warmed up, in closed loop operating mode for accurate idle adjustment.

Adjustment Procedure

1. Make sure there are no fault codes present in the ECU memory.

2. Start the engine and allow it to fully warm up and establish closed looped operation (approximately 5-10 min.).

3. Place the thro le control in the idle/slow position and check the idle speed with a tachometer. Turn the idle speed screw in or out as required to obtain 1500 RPM, or the idle speed speciﬁ ed by the equipment manufacturer. See Figure 5-23.

4. If the idle speed is adjusted up over 1800 RPM, you must ﬁ rst decrease idle RPM to 1500 RPM and then up to ﬁ nal idle speed se ing for the TPS to be properly learned by the ECU.

5. The idle speed adjustment can aﬀ ect the high idle speed se ing. Move the thro le control to the full thro le position and check the high idle speed. Adjust as necessary to 3750 RPM, or the speed speciﬁ ed by the equipment manufacturer.

If the governor/thro le components are all intact, but you think there may be a problem with the adjustment, follow Procedure A to check the se ing. If the governor lever or the thro le body was loosened or removed, go immediately to Procedure B to perform the initial adjustment.

Throttle

Damper Spring

Figure 5-24. Throttle Linkage/Governor Lever Connection.

A. Checking the Initial Adjustment

1. Unsnap the plastic linkage bushing a aching the thro le linkage to the governor lever. See Figure 5-24. Unhook the damper spring from the lever, separate the linkage from the bushing, and remove the bushing from the lever. Mark the hole position and unhook the governor spring from the governor lever.

2. Pivot the thro le sha and plate assembly into the Full Thro le position. Use a locking pliers (needle nose works best) to temporarily clamp the plate to the stop boss. Alternatively, there may be a stop pin instead of the stop boss. See Figure 5-25.

High-Speed Throttle Stop Boss

Linkage

Linkage Bushing

Initial Governor Adjustment

The initial governor adjustment is especially critical on EFI engines because of the accuracy and sensitivity of the electronic control system. Incorrect adjustment can result in overspeed, loss of power, lack of response, or inadequate load compensation. If you encounter any of these symptoms and suspect them to be related to the governor se ing, the following should be used to check and/or adjust the governor and thro le linkage.

5.24

High-Speed Throttle Stop Pin

Figure 5-25. Throttle Details.

Section 5

EFI Fuel System

3. Rotate the governor lever and sha counterclockwise until it stops. Use only enough pressure to hold it in that position.

4. Check how the end of the thro le linkage aligns with the bushing hole in the governor lever. See Figure 5-26. It should fall in the center of the hole. If it doesn’t, perform the adjustment procedure as follows.

Figure 5-26. Throttle Link in Center of Hole.

B. Setting the Initial Adjustment

1. Check the split where the clamping screw goes through the governor lever. See Figure 5-27. There should be a gap of at least 1/32 in. If the tips are touching and there is no gap present, the lever should be replaced. If not already installed, position the governor lever on the cross sha , but leave the clamping screw loose.

3. Insert a nail or Allen wrench into the hole in the top of the cross sha . Using light pressure, rotate the governor sha counterclockwise as far as it will turn, then torque the hex nut on the clamping screw to 6.8 N·m (63 in. lb.). See Figure 5-28. Make sure that the governor arm has not twisted up or down a er the nut has been tightened.

Figure 5-28. Adjusting Governor Shaft.

4. Verify that the governor has been set correctly. With the linkage still retained in the Full Thro le position (Step 2), unsnap the bushing clip, separate the linkage from the bushing, and remove the bushing from the lever. Follow Steps 3 and 4 in Checking the Initial Adjustment.

5. Reconnect the dampening spring into its governor lever hole from the bo om. Reinstall the bushing and rea ach the thro le linkage. See Figure 5-24. Rea ach the governor spring in the marked hole.

Figure 5-27. Checking Split of Clamp.

2. Follow the instructions in Step 2 of Checking the Initial Adjustment, then rea ach the thro le linkage to the governor lever with the bushing clip. It is not necessary to rea ach the damper or governor springs at this time.

6. Start the engine and allow it to fully warm up and establish closed loop operation (approximately 5-10 min.). Check the speed se ings and adjust as necessary, ﬁ rst the low idle speed, and then the high-speed se ing.

NOTE: Thro le body and air cleaner assembly

must be securely fastened with three hex ﬂ ange nuts to the intake manifold prior to a empting to set the governor.

5.25

Section 5 EFI Fuel System

Troubleshooting

General

When troubleshooting a problem on an engine with EFI, basic engine operating problems must be eliminated ﬁ rst before faulting the EFI system components. What appears to be an EFI problem could be something as simple as a fuel tank with debris in the bo om or a plugged vent. Be sure the engine is in good mechanical operating condition and all other systems are operating properly before a empting to troubleshoot the EFI system.

Troubleshooting Guide

Engine starts hard or fails to start when cold

1. Fuel pump not running

2. Faulty spark plugs

3. Old/stale fuel

4. Incorrect fuel pressure

5. Cranksha position sensor loose or faulty

6. TPS set incorrect (ECU Reset and TPS Learn)

7. TPS faulty

8. Engine temp sensor faulty

9. Faulty coils

10. Low system voltage

11. Faulty injectors

12. Faulty ba ery

13. Loose or corroded connections

Engine starts hard or fails to start when hot

1. Faulty spark plugs

2. Fuel pump not running

3. Fuel pressure low

4. Insuﬃ cient fuel delivery

5. TPS set incorrect (ECU Reset and TPS Learn)

6. Cranksha position sensor loose or faulty

7. TPS faulty

8. Engine temp sensor faulty

9. Faulty injectors

Engine misses, hesitates, or stalls under load

1. Fuel injector(s), fuel ﬁ lter, fuel line, or fuel pick-up dirty/restricted

2. Dirty air cleaner

3. Insuﬃ cient fuel pressure or fuel delivery

4. Vacuum (intake air) leak

5. Improper governor se ing, adjustment or operation

6. TPS faulty, mounting problem or TPS Learn Procedure incorrect

7. Bad coil(s), spark plug(s), or wires

Low Power

1. Faulty/malfunctioning ignition system

2. Dirty air ﬁ lter

3. Insuﬃ cient fuel delivery

4. Improper governor adjustment

5. Plugged/restricted exhaust

6. One injector not working

7. Basic engine problem exists

8. TPS faulty or mounting exists

9. Thro le plate in thro le body not fully opening to WOT stop (if so equipped)

Fuel System

WARNING: Fuel System Under Pressure!

The fuel system operates under high pressure. System pressure must be relieved through the fuel connector and the fuel pump module (see page 5.2) prior to servicing or removal of any fuel system components. Do not smoke or work near heaters or other ﬁ re hazards. Have a ﬁ re extinguisher handy and work only in a well-ventilated area.

The function of the fuel system is to provide suﬃ cient delivery of fuel at the system operating pressure of 39 psi ± 3. If an engine starts hard, or turns over but will not start, it may indicate a problem with the EFI fuel system. A quick test will verify if the system is operating.

Engine stalls or idles roughly (cold or warm)

1. Faulty spark plugs

2. Insuﬃ cient fuel delivery

3. TPS set incorrect

4. TPS faulty

5. Faulty engine temperature sensor

6. Faulty injectors

5.26

1. Disconnect and ground the spark plug leads.

2. Complete all safety interlock requirements and crank the engine for approximately 3 seconds.

Section 5

EFI Fuel System

3. Remove the spark plugs and check for fuel at the tips.

a. If there is fuel at the tips of the spark plugs the

fuel pump and injectors are operating.

b. If there is no fuel at the tips of the spark plugs,

check the following:

1) Make sure the fuel tank contains clean,

fresh, proper fuel.

2) Make sure that the vent in the fuel tank is

open.

3) Make sure the fuel tank valve (if so

equipped) is fully opened.

4) Make sure the ba ery is supplying proper

voltage.

5) Check that the fuses are good, and that no

electrical or fuel line connections are damaged or broken.

4. The MIL will blink a series of times. The number of times the MIL blinks represents a number in the blink code.

5. A sequence of four digits make up a fault code. There is a one (1) second pause between the blinks of a fault code. There is a three (3) second pause between separate fault codes. A er the fault code(s) are blinked a two digit 61 is blinked to indicate the program has completed.

a. It’s a good idea to write down the codes as

they appear, as they may not be in numerical sequence.

b. Code 61 will always be the last code

displayed, indicating the end of code transmission. If code 61 appears immediately, no other fault codes are present.

6) Test fuel pump module operation as described earlier under Fuel Pump – Service.

Fault Codes

The ECU continuously monitors engine operation against preset performance limits. If the operation is outside the limits, the ECU activates the MIL, if equipped, and stores a diagnostic code in its fault memory. If the component or system returns to proper function, the ECU will turn oﬀ the MIL. If the MIL stays illuminated, it warns the customer a fault is currently happening, and dealer service is required. Upon receipt, the dealer technician can access the fault code(s) to help determine what portion of the system is malfunctioning. The 4-digit fault codes available are listed on page 5.29.

The codes are accessed through the key switch and displayed as blinks or ﬂ ashes of the MIL. Access the codes as follows:

1. Check that the ba ery voltage is above 11 volts.

2. Start with the key switch OFF.

3. Turn the key switch to the ON and OFF, then ON

and OFF, then ON, leaving it on in the third sequence. Do not start the engine. The time between sequences must be less than 2.5 seconds.

5.27

Section 5 EFI Fuel System

Example of Diagnostic Display

One second pause

(0)

(1)

One second pause

(0)

One second pause

Fault Code 0107

(7)

Three second pause

(6)

One second pause

(1)

This is a 0107 fault code with the 61 message end code. Figure 5-29.

A er the problem has been corrected, the fault codes may be cleared by following the ECU Reset and TPS Learn Procedures.

The chart on the following page lists the fault codes, and what they correspond to. Following the chart is a list of the individual codes with an explanation of what triggers them, what symptoms might be expected, and the probable causes.

End Code 61

A MIL may not be provided with the engine. If the equipment manufacturer has not added a MIL to the equipment, one can be added easily for quick diagnostics. The main engine to vehicle connection will have a tan wire which is the ground for the MIL. Either incandescent or LED type bulbs can be used for the MIL as long as they do not draw more than 0.1 amps. The bulb needs to be rated at 1.4 Wa s or less, or needs to have a total resistance of 140 Ω or more. LEDs typically draw less than 0.03 amps. Attach +12 volts to the positive terminal of the bulb and attach the ground terminal of the bulb to the tan wire.

5.28

Diagnostic Code Summary

Fault Code Connection or Failure Description

0031 Oxygen Sensor Heater Circuit High Voltage

0032 Oxygen Sensor Heater Circuit Low Voltage

0107 Manifold Absolute Pressure Sensor Circuit Low Voltage or Open

0108 Manifold Absolute Pressure Sensor Circuit High Voltage

0112 Intake Air Temperature Sensor Circuit Low Voltage

0113 Intake Air Temperature Sensor Circuit High Voltage or Open

0117 Coolant/Oil Temperature Sensor Circuit Low Voltage

0118 Coolant/Oil Temperature Sensor Circuit High Voltage or Open

Section 5

EFI Fuel System

0122 Thro le Position Sensor Circuit Low Voltage or Open

0123 Thro le Position Sensor Circuit High Voltage

0131 Oxygen Sensor 1 Circuit Low Voltage, or Open

0132 Oxygen Sensor 1 Circuit High Voltage

0171 Maximum Adaptation Limit Exceeded

0172 Minimum Adaptation Limit Exceeded

0174 Lean Fuel Condition at High Load (Open Loop)

0201 Injector 1 Circuit Malfunction

0202 Injector 2 Circuit Malfunction

0230 Fuel Pump Module Circuit Low Voltage or Open

0232 Fuel Pump Module Circuit High Voltage

0336 Cranksha Position Sensor Noisy Signal

0337 Cranksha Position Sensor No Signal

0351 Cylinder 1 Ignition Coil Malfunction

0352 Cylinder 2 Ignition Coil Malfunction

0562 System Voltage Low

0563 System Voltage High

61 End of Code Transmission

5.29

Section 5 EFI Fuel System

Code: 0031

Component: Oxygen Sensor Heater

Fault: O2S Heater Circuit High Voltage

Condition: System voltage too high, shorted connection or faulty sensor.

Possible Causes:

1. Oxygen Sensor Related a. Sensor connector or wiring problem. b. Sensor damaged. c. Pin circuit wiring or connectors at Black 7.

2. ECU Related a. ECU-to-harness connection problem.

Code: 0032

Component: Oxygen Sensor Heater

Fault: O2S Heater Circuit Low Voltage

Condition: System voltage too low, open connection or faulty sensor.

Possible Causes:

1. Engine Wiring Harness Related a. Pin circuit wiring or connectors.

1. ECU Black pin 7.

2. Broken wire.

2. Oxygen Sensor Related a. Sensor connector or wiring problem.

3. Poor system ground from ECU to engine or ba ery to engine.

Code: 0108

Component: Manifold Absolute Pressure Sensor

Fault: MAP Circuit High Voltage

Condition: Intake manifold leak, shorted connection or faulty sensor.

Possible Causes:

1. MAP Sensor Related a. Sensor malfunction. b. Vacuum leaks from loose manifold or sensor.

2. Wire Harness Related a. Poor grounding. b. Pin circuit wiring or connectors at Black 11.

3. Bad TPS Learn.

Code: 0112

Component: Intake Air Temperature Sensor

Fault: Intake Air Temperature Sensor

Circuit Low Voltage Condition: Shorted connection, faulty sensor or shorted wire.

Possible Causes:

1. Temperature Sensor Related a. Sensor wiring or connection.

2. Engine Wiring Harness Related a. Pin circuits Black 10 and Black 8 may be

damaged or routed near noisy signal (coils, alternator, etc.).

b. ECU-to-harness connection problem.

Code: 0107

Component: Manifold Absolute Pressure Sensor

Fault: MAP Circuit Low Voltage or Open

Condition: Intake manifold leak, open connection or faulty sensor.

Possible Causes:

1. MAP Sensor Related a. Sensor malfunction. b. Vacuum leaks from loose manifold or sensor.

2. Wire Harness Related a. Poor grounding or open circuit. b. Wire harness and connectors loose, damaged

or corroded.

c. Pin circuit wiring or connectors at Black 10, 11

and 16.

3. Bad TPS Learn.

5.30

Code: 0113

Component: Intake Air Temperature Sensor

Fault: Intake Air Temperature Sensor

Circuit High Voltage or Open Condition: Shorted connection, faulty sensor, broken wire or connection.

Possible Causes:

1. Temperature Sensor Related a. Sensor wiring or connection.

2. Engine Wiring Harness Related a. Pin circuits ECU Black pin 10 and 8 may be

damaged.

b. ECU-to-harness connection problem or

broken wire.

Section 5

EFI Fuel System

Code: 0117

Component: Coolant/Oil Sensor

Fault: Coolant/Oil Temperature Sensor

Circuit Low Voltage Condition: Shorted connection, faulty sensor or shorted wire.

Possible Causes:

1. Temperature Sensor Related a. Sensor wiring or connection.

2. Engine Wiring Harness Related a. Pin circuits Black 10 and Black 14 maybe

damaged or routed near noisy signal (coils, stator, etc.).

b. ECU-to-harness connection problem.

Code: 0118

Component: Coolant/Oil Sensor

Fault: Coolant/Oil Temperature Sensor

Circuit High Voltage or Open Condition: Shorted connection, faulty sensor, open connection or broken wire.

Possible Causes:

1. Temperature Sensor Related a. Sensor wiring or connection.

3. ECU Black pin 16 to TPS pin 2.

3. Thro le Body Related a. Thro le sha inside TPS worn, broken, or

damaged. b. Thro le plate loose or misaligned. c. Thro le plate bent or damaged allowing extra

airﬂ ow past, or restricting movement.

4. ECU Related a. Circuit providing voltage or ground to TPS

damaged. b. TPS signal input circuit damaged.

Code: 0123

Component: Thro le Position Sensor (TPS)

Fault: TPS Circuit High Voltage

Condition: Shorted connection or faulty sensor.

Possible Causes:

1. TPS Sensor Related a. Sensor connector or wiring. b. Sensor output aﬀ ected or disrupted by dirt,

grease, oil, wear. c. Sensor loose on thro le body manifold.

2. Thro le Body Related a. Thro le sha or bearings worn/damaged.

2. Engine Wiring Harness Related a. Pin circuits ECU Black pin 10 and 14 may be

damaged.

b. ECU-to-harness connection problem or

broken wire.

3. System Related a. Engine is operating above the 176°C (350°F)

temperature sensor limit.

Code: 0122

Component: Thro le Position Sensor (TPS)

Fault: TPS Circuit Low Voltage or Open

Condition: Open connection, broken wire or faulty sensor.

Possible Causes:

1. TPS Related a. TPS bad or worn internally.

2. Engine Wiring Harness Related a. Broken or shorted wire in harness.

1. ECU Black pin 10 to TPS pin 1.

2. ECU Black pin 12 to TPS pin 3.

3. Engine Wiring Harness Related a. ECU pins Black 10, 12 and 16 damaged

(wiring, connectors). b. ECU pins Black 10, 12 and 16 routed near

noisy electrical signal (coils, alternator). c. Intermi ent 5 volt source from ECU (pin

Black 16). d. ECU-to-harness connection problem.

Code: 0131

Component: Oxygen Sensor

Fault: O2S 1 Circuit Low Voltage

Condition: Open connection, broken wire or faulty sensor.

Possible Causes:

1. Oxygen Sensor Related a. Sensor connector or wiring problem. b. Sensor contaminated, corroded or damaged. c. Poor ground path. d. Pin circuit wiring or connectors. ECU Black pin 10 or 17.

5.31

Section 5 EFI Fuel System

2. TPS Learn Procedure Incorrect a. Lean condition (check oxygen sensor signal

with VOA and see Oxygen Sensor section).

3. Engine wiring harness related such as a cut wire, broken or pinched.

Code: 0132

Component: Oxygen Sensor

Fault: O2S 1 Circuit High Voltage

Condition: Shorted connection or faulty sensor.

Possible Causes:

1. Oxygen Sensor Related

a. Sensor connector or wiring problem. b. Sensor contaminated or damaged. c. Poor ground path. d. Pin circuit wiring or connectors. ECU Black pin 10 or Black pin 17.

2. Engine Wiring Harness Related

a. Diﬀ erence in voltage between sensed voltage

and actual sensor voltage.

b. Short in wire harness.

Code: 0171

Component: Fuel System

Fault: Maximum adaptation limit

exceeded Condition: Fuel inlet screen/ﬁ lter plugged, low pressure at high pressure fuel line, TPS malfunction, shorted connection, faulty sensor, low fuel or wrong fuel type.

Possible Causes:

1. Oxygen Sensor Related a. Corrosion or poor connection. b. Sensor contaminated or damaged. c. Air leak into exhaust. d. Poor ground path. e. Pin circuit wiring or connectors.

1. ECU Black pin 10 or Black pin 17.

2. TPS Sensor Related a. Thro le plate position incorrect during Learn

procedure.

b. TPS problem or malfunction.

4. Systems Related a. Ignition (spark plug, plug wire, ignition coil). b. Fuel (fuel type/quality, injector, fuel pressure

too low, fuel pump module or li pump).

c. Combustion air (air cleaner dirty/restricted,

intake leak, thro le bores). d. Base engine problem (rings, valves). e. Exhaust system leak (muﬄ er, ﬂ ange, oxygen

sensor mounting boss, etc.). f. Fuel in the crankcase oil.

Code: 0172

Component: Fuel System

Fault: Minimum adaptation limit exceeded

Condition: Too high pressure at high pressure fuel line, TPS malfunction, shorted connection, faulty sensor or fuel pump module failure.

Possible Causes:

1. Oxygen Sensor Related a. Sensor connector or wiring. b. Sensor contaminated or damaged. c. Poor ground path. d. Pin circuit wiring or connectors. ECU Black pin 10 or 17.

2. TPS Sensor Related a. Thro le plate position incorrect during Learn

procedure. b. TPS problem or malfunction.

3. Engine Wiring Harness Related a. Diﬀ erence in voltage between sensed voltage

and actual sensor voltage. b. Problem in wiring harness. c. ECU-to-harness connection problem.

4. Systems Related a. Ignition (spark plug, plug wire, ignition coil). b. Fuel (fuel type/quality, injector, fuel pressure

too high, fuel pump module or li pump). c. Combustion air (air cleaner dirty/restricted). d. Base engine problem (rings, valves). e. Fuel in the crankcase oil. f. Fuel pump module is over ﬁ lled. g. Li pump diaphragm is ruptured.

3. Engine Wiring Harness Related a. Diﬀ erence in voltage between sensed voltage

and actual sensor voltage. b. Problem in wiring harness. c. ECU-to-harness connection problem.

5.32

Section 5

EFI Fuel System

Code: 0174

Component: Fuel System

Fault: Lean fuel condition

Condition: Fuel inlet screen/ﬁ lter plugged, low pressure at high pressure fuel line, TPS malfunction, shorted connection or faulty sensor.

Possible Causes:

1. TPS Learn Incorrect a. Lean condition (check oxygen sensor signal

with VOA and see Oxygen Sensor section).

2. Engine Wiring Harness Related a. Pin circuit wiring or connectors. ECU pin Black 10, 12, 16 and 17.

3. Low Fuel Pressure a. Plugged ﬁ lters. b. Bad li pump.

4. Oxygen Sensor Related a. Sensor connector or wiring problem. b. Exhaust leak. c. Poor ground.

Code: 0202

Component: Fuel Injector

Fault: Injector 2 Circuit Malfunction

Condition: Injector damaged or faulty, shorted or open connection.

Possible Causes:

1. Injector Related a. Injector coil shorted or opened.

2. Engine Wiring Harness Related a. Broken or shorted wire in harness. ECU pin Black 6. b. Wiring from Ignition.

3. ECU Related a. Circuit controlling injector #2 damaged.

Code: 0230

Component: Fuel Pump

Fault: Circuit Low Voltage or Open

Condition: Shorted or open connection.

5. Poor system ground from ECU to engine, causing rich running while indicating lean.

6. Fuel pump module connection. See Fuel Components.

Code: 0201

Component: Fuel Injector

Fault: Injector 1 Circuit Malfunction

Condition: Injector damaged or faulty, shorted or open connection.

Possible Causes:

1. Injector Related

a. Injector coil shorted or opened.

2. Engine Wiring Harness Related

a. Broken or shorted wire in harness. ECU pin Black 5. b. Wiring from Ignition.

3. ECU Related

a. Circuit controlling injector #1 damaged.

Possible Causes:

1. Fuel Pump Related a. Fuel pump module open or shorted internally.

2. Engine Wiring Harness related a. Broken or shorted wire in harness. ECU pin Black 9 or Grey 17.

3. ECU Related a. The ECU is damaged.

Code: 0232

Component: Fuel Pump

Fault: Circuit High Voltage

Condition: Shorted connection.

Possible Causes:

1. Fuel Pump Related a. Fuel pump module damaged internally.

2. Charging Output System Too High.

5.33

Section 5 EFI Fuel System

Code: 0336

Component: Cranksha Position Sensor

Fault: Cranksha Position Sensor Noisy

Signal Condition: Air gap incorrect, loose sensor, faulty/bad ba ery, shorted or faulty connection, faulty sensor or faulty sensor grounding.

Possible Causes:

1. Cranksha Position Sensor Related a. Sensor connector or wiring. b. Sensor loose or air gap incorrect.

2. Cranksha Position Sensor Wheel Related a. Damaged teeth. b. Gap section not registering.

3. Engine Wiring Harness Related a. Pin circuit wiring or connectors. ECU pin Black 4 and Black 13. b. ECU-to-harness connection problem.

4. Ignition System Related a. Non-resistor spark plug(s) used. b. Faulty or disconnected ignition coil or

secondary lead.

Code: 0337

Component: Cranksha Position Sensor

Fault: Cranksha Position Sensor No

Signal Condition: Air gap incorrect, loose sensor, open or shorted connection or faulty sensor.

Possible Causes:

1. Cranksha Position Sensor Related a. Sensor connector or wiring. b. Sensor loose or air gap incorrect.

Code: 0351

Component: Ignition Coil

Fault: Cylinder 1 Ignition Coil Malfunction

Condition: Broken wire in harness (may not be visible), shorted connection or faulty sensor.

Possible Causes:

1. Engine Wiring Harness Related a. Connection to ignition or fuse. b. Pin circuit wiring or connectors. ECU pin Black 1. c. ECU-to-harness connection problem.

2. Ignition System Related a. Incorrect spark plug(s) used. b. Poor connection to spark plug.

Code: 0352

Component: Ignition Coil

Fault: Cylinder 2 Ignition Coil Malfunction

Condition: Broken wire in harness (may not be visible), shorted connection or faulty sensor.

Possible Causes:

1. Engine Wiring Harness Related a. Connection to ignition or fuse. b. Pin circuit wiring or connectors. ECU pin Grey 10. c. ECU-to-harness connection problem.

2. Ignition System Related a. Incorrect spark plug(s) used. b. Poor connection to spark plug.

Code: 0562

Component: System Voltage

2. Cranksha Position Sensor Wheel Related a. Damaged teeth.

3. Engine Wiring Harness Related a. Pin circuit wiring or connectors. ECU pin Black 4 or Black 13. b. ECU-to-harness connection problem.

4. If code is stored in fault history and starts

normally. Clear code, no other service required.

5.34

Fault: System Voltage Low

Condition: Faulty voltage regulator, bad fuse or shorted connection.

Possible Causes:

1. Corroded Connections

2. Bad Stator

3. Bad Ba ery a. Low output charging system. b. Poor magnet in ﬂ ywheel. c. Bad or missing fuse.

Section 5

EFI Fuel System

Code: 0563

Component: System Voltage

Fault: System Voltage High

Condition: Faulty voltage regulator or shorted connection.

Possible Causes:

1. Faulty Rectiﬁ er-Regulator

2. Bad Stator.

3. Bad Ba ery.

Code: 61 Fault: End of Code Transmission

Troubleshooting Flow Chart

The following ﬂ ow chart provides an alternative method of troubleshooting the EFI system. The chart will enable you to review the entire system in about 10-15 minutes. Using the chart, the accompanying diagnostic aids (listed a er the chart), and any signaled fault codes, you should be able to quickly locate any problems within the system. See Figure 5-30.

5.35

Section 5 EFI Fuel System

START OF TEST

KEY ON

EFI Diagnostic Flow Diagram

PROCEED TO START OF TEST FOR RETEST

MALFUNCTION

INDICATOR LIGHT

ARE FAULT CODES

PRESENT?

DOES ENGINE START?

CRANK ENGINE.

DOES MIL GO OFF?

YES

KEY OFF AND KEY ON

LISTEN FOR FUEL PUMP.

DOES FUEL PUMP CYCLE

ON THEN OFF AFTER 1–2

SECONDS

YES

WHILE CRANKING, CHECK

IGNITION SYSTEM

YES

YES MIL GOES OFF?

YES

REFER TO DIAGNOSTIC AID #1

SYSTEM POWER

REFER TO DIAGNOSTIC AID #2

FAULT CODES

CLEAR CODES

REFER TO DIAGNOSTIC AID #3

OPERATE AT VARIOUS SPEED/

REFER TO DIAGNOSTIC AID #4

CRANKSHAFT POSITION SENSOR

REFER TO DIAGNOSTIC AID #5

RUN/ON

LOAD CONDITIONS

ARE FAULT CODES

PRESENT?

END OF TEST

FUEL PUMP

REFER TO DIAGNOSTIC

YES

AID #2 FAUL T CODES

CLEAR CODES

PROCEED TO START OF TEST FOR RETEST

SPARK?

YES

WHILE CRANKING, CHECK

INJECTOR FUEL DELIVERY.

WET SPARK PLUG?

YES

INSTALL IN-LINE PRESSURE

GAUGE AND KEY ON.

FUEL PRESSURE

IN SPECIFICATION?

1. After turning key to OFF, wait 10 seconds before turning to ON to allow the ECU to go to sleep.

2. The fuel pump module can be heard or a vibration can be felt to establish pump cycle. Fuel pump module will run for one 4-6 second cycle when ECU wakes up after being asleep.

YES

Figure 5-30. Troubleshooting Flow Chart.

5.36

REFER TO DIAGNOSTIC AID #6

IGNITION SYSTEM

REFER TO DIAGNOSTIC AID #7

FUEL SYSTEM ELECTRICAL

REFER TO DIAGNOSTIC AID #8

FUEL SYSTEM

REFER TO DIAGNOSTIC AID #9

BASIC ENGINE

Section 5

EFI Fuel System

Flow Chart Diagnostic Aids

Diagnostic Aid #1 SYSTEM POWER

(MIL does not illuminate when key is turned ON)

NOTE: MIL is installed by vehicle OEM. Twelve volt

supply to bulb will be part of vehicle wire harness. Kohler key switch model will have MIL on engine with 12V supply to bulb.

Possible causes:

1. Ba ery

2. Main system fuse

3. MIL light bulb burned out

4. MIL electrical circuit problem Pin circuits Grey 3.

5. Ignition switch

6. Permanent ECU power circuit problem Pin circuit Black 18.

7. Switched ECU power circuit problem Pin circuit Black 15. 8 ECU grounds

9. ECU

Diagnostic Aid #2 FAULT CODES

(Refer to detailed fault code listing before ﬂ ow chart and servicing information for the respective components)

Code 0230 - Fuel Pump Module Circuit Low Voltage

or Open Code 0232 - Fuel Pump Module Circuit High Voltage Code 0336 - Cranksha Position Sensor Noisy Signal Code 0337 - Cranksha Position Sensor No Signal Code 0351 - Cylinder 1 Ignition Coil Malfunction Code 0352 - Cylinder 2 Ignition Coil Malfunction Code 0562 - System Voltage Low Code 0563 - System Voltage High Code 61 - End of Code Transmission.

Diagnostic Aid #3 RUN/ON

(MIL remains ON while engine is running)*

Possible causes:

1. All current fault codes will turn on MIL when

engine is running.

NOTE: Either incandescent or LED type bulbs can

be used for the MIL as long as they do not draw more than 0.1 amps. The bulb needs to be rated at 1.4 Wa s or less, or needs to have a total resistance of 140 Ω or more. LEDs typically draw less than 0.03 amps.

Diagnostic Aid #4 CRANKSHAFT POSITION SENSOR

(MIL does not turn oﬀ during cranking)

Code 0031 - Oxygen Sensor Heater Circuit High

Voltage

Code 0032 - Oxygen Sensor Heater Circuit Low

Voltage

Code 0107 - Manifold Absolute Pressure Sensor

Circuit Low Voltage or Open

Code 0108 - Manifold Absolute Pressure Sensor

Circuit High Voltage

Code 0112 - Intake Air Temperature Sensor

Circuit Low Voltage

Code 0113 - Intake Air Temperature Sensor

Circuit High Voltage or Open

Code 0117 - Coolant/Oil Temperature Sensor

Circuit Low Voltage

Code 0118 - Coolant/Oil Temperature Sensor

Circuit High Voltage or Open Code 0122 - TPS Circuit Low Voltage or Open Code 0123 - TPS Circuit High Voltage Code 0131 - O2S 1 Circuit Low Voltage or Open Code 0132 - O2S 1 Circuit High Voltage Code 0171 - Maximum adaptation limit exceeded Code 0172 - Minimum adaptation limit exceeded Code 0174 - Lean fuel condition at high load or open

loop Code 0201 - Injector 1 Circuit Malfunction Code 0202 - Injector 2 Circuit Malfunction

Possible causes:

1. Cranksha position sensor

2. Cranksha position sensor circuit problem, pin circuits Black 4 and Black 13.

3. Cranksha position sensor/toothed wheel air gap

4. Toothed wheel

5. Flywheel key sheared

6. ECU

Diagnostic Aid #5 FUEL PUMP

(fuel pump not turning on)

Possible causes:

1. Main fuse

2. Fuel pump circuit problem, pin circuits Black 9 and Grey 17.

3. Fuel pump module

Diagnostic Aid #6 IGNITION SYSTEM

(no spark)

Possible causes:

1. Spark plug

2. Plug wire

3. Coil

4. Coil circuit(s), pin circuits Grey 10 and Black 1.

5. ECU grounds

5.37

Section 5 EFI Fuel System

6. ECU

7. Vehicle safety interlocks, ground signal on safety wire.

Diagnostic Aid #7 FUEL SYSTEM ELECTRICAL

(no fuel delivery)

Possible causes:

1. No fuel

2. Air in high pressure fuel line

3. Fuel valve shut OFF

4. Fuel ﬁ lter/line plugged

5. Injector circuit(s), pin circuits Black 5 and Black 6

6. Injector

7. ECU grounds

8. ECU

9. Li pump not working

Diagnostic Aid #8 FUEL SYSTEM

(fuel pressure)

Possible causes for low fuel system pressure:

1. Low fuel

2. Fuel ﬁ lter plugged

3. Fuel supply line plugged

4. Li fuel pump - insuﬃ cient fuel supply

5. Fuel pump (li or module) - internally plugged

Possible causes for high fuel system pressure:

1. Pressure regulator not functioning properly inside fuel pump module.

Diagnostic Aid #9 BASIC ENGINE

(cranks but will not run)

Possible causes:

1. Refer to basic engine troubleshooting charts within service manual sections 3, 5, and 7.

5.38

Section 6

Lubrication System

General

This engine uses a full pressure lubrication system. This system delivers oil under pressure to the cranksha , camsha , and connecting rod bearing surfaces. In addition to lubricating the bearing surfaces, the lubrication system supplies oil to the hydraulic valve li ers.

A high-eﬃ ciency gerotor pump is located in the closure plate. The oil pump maintains high oil ﬂ ow and oil pressure, even at low speeds and high operating temperatures. A pressure relief valve limits the maximum pressure of the system.

Service

The closure plate must be removed to service the oil pickup, the pressure relief valve and the oil pump. Refer to the appropriate procedures in Sections 8 and

Oil Recommendations

Using the proper type and weight of oil in the crankcase is extremely important; so is checking oil daily and changing the oil and ﬁ lter regularly.

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 6-2.

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.

Kohler 10W-30

10W-30

SAE 30

5W-30

°F -20 020324060

°C -30 -20 -10 0 10 20 30 40

Figure 6-1. Viscosity Grade Table.

50 80 100

Figure 6-2. Oil Container Logo.

The top position of the symbol shows service class such as API SERVICE CLASS SJ. The symbol may show additional categories such as SH, SG/CC, or CD. The center portion shows the viscosity grade such as SAE 10W-30. If the bo om portion shows Energy Conserving, it means that oil is intended to improve fuel economy in passenger car engines.

6.1

Section 6 Lubrication System

Check Oil Level

The importance of checking and maintaining the proper oil level in the crankcase cannot be overemphasized. Check oil BEFORE EACH USE as follows:

1. Make sure the engine is stopped, level and is cool so the oil has had time to drain into the sump.

2. Clean the area around the dipstick before removing it. This will help to keep dirt, grass clippings, etc., out of the engine.

3. Remove the dipstick; wipe oil oﬀ . Reinsert the dipstick into the tube until fully seated. See Figure 6-3.

Dipstick

Oil Fill Cap (Valve Cover Location)

NOTE: To prevent extensive engine wear or damage,

always maintain the oil level in the correct operating range. Never operate the engine with the oil level below the L mark or above the F mark on the dipstick.

Oil Disposal

Protect and respect the environment. Dispose of oil at your local recycling center or municipal collection center in accordance with local ordinances

Changing Oil and Oil Filter

Changing Oil

Change the oil a er every 100 hours of operation (more frequently under severe conditions). Reﬁ ll with oil as speciﬁ ed in the Recommended Viscosity Grades Table.

Change the oil while the engine is still warm. The oil will ﬂ ow more freely and carry away more impurities. Make sure the engine is level when ﬁ lling or checking oil.

Figure 6-3. Location of Oil Fill Cap and Dipstick.

4. Remove dipstick and check oil level. The

level should be between the F and L marks. If low, add oil of the proper type (refer to Oil Recommendations on page 6.1) up to the F mark. Reinstall oil ﬁ ll cap and dipstick.

Operating

Range

Change the oil as follows:

1. To keep dirt, debris, etc., out of the engine, clean the area around the dipstick; remove the dipstick.

2. Remove the oil drain plug on the starter side or the drain plug oil ﬁ lter side. Allow ample time for complete drainage. See Figures 6-5 and 6-6.

Oil Drain Plug Starter Side

Figure 6-5. Location of Oil Drain (Starter Side).

Figure 6-4. Oil Level Marks on Dipstick.

6.2

Oil Drain Plug Oil Filter Side

Check Oil Level

Figure 6-6. Location of Oil Drain (Oil Filter Side).

Section 6

Lubrication System

Figure 6-8. Removing Oil Filter.

3. Reinstall the drain plug and torque to 13.6 N·m (10  . lb.).

4. Remove the ﬁ ll cap or use the dipstick ﬁ ll tube to ﬁ ll the crankcase with new oil of the proper type

to the F or FULL mark on the dipstick. See Figure 6-7. Recheck oil level before adding more oil.

Figure 6-7. Removing Oil Fill Cap.

5. Reinstall the oil ﬁ ll cap and dipstick securely.

1. To keep dirt, debris, etc., out of the engine, clean the area around the dipstick; remove the dipstick.

Remove the oil drain plug on the starter side or the drain plug oil ﬁ lter side. Allow ample time for

complete drainage. See Figures 6-3, 6-5 and 6-6

2. Reinstall the drain plug and torque to 13.6 N·m (10  . lb.).

3. To keep dirt, debris, etc., out of the engine, clean the area around the oil ﬁ lter; remove the oil ﬁ lter. See Figure 6-8.

4. Wipe the surface where the oil ﬁ lter mounts.

5. Place a new ﬁ lter in a shallow pan with the open end up. Pour new oil, of the proper type, in through the threaded center hole. Stop pouring when the oil reaches the bo om of the threads. Allow a minute or two for the oil to be absorbed by the ﬁ lter material.

6. Apply a thin ﬁ lm of clean oil to the rubber gasket on the new ﬁ lter.

Changing Oil Filter

Replace the oil ﬁ lter at least every other oil change (every 200 hours of operation). Always use a genuine

Kohler oil ﬁ lter. Replace the oil ﬁ lter as follows. See Figure 6-8.

7. Install the oil ﬁ lter to the ﬁ lter adaptor or oil cooler. Refer to instructions on the oil ﬁ lter for proper installation.

8. Remove the ﬁ ll cap (see Figure 6-7) or use the dipstick ﬁ ll tube to ﬁ ll the crankcase with new oil of the proper type to the F or FULL mark on the dipstick. Recheck oil level before adding more oil. (Refer to

9. Reinstall the oil ﬁ ll cap and dipstick securely.

Check Oil Level.)

6.3

Section 6

Oil Cooler

Lubrication System

10. Test run the engine to check for leaks. Stop the engine, allow a minute for the oil to drain down, and recheck the level on the dipstick. Verify the oil level is up to but not over the F or FULL mark on the dipstick. See Figure 6-4.

Service Oil Cooler

Some engines are equipped with an optional oil cooler. Inspect and clean oil cooler every 100 hours of operation (more frequently under severe conditions). Oil cooler must be kept free of debris. Service the oil cooler as follows:

1. Clean the outside of the ﬁ ns with a brush or compressed air.

2. Remove the hardware securing the oil cooler to the blower housing.

3. Clean the inside of the cooler with a brush or compressed air.

4. Reinstall the oil cooler to the blower housing with the mounting hardware. See Figure 6-9.

Oil Cooler

Oil Sentry

General

Some engines are equipped with an optional Oil Sentry™ switch. This switch is designed to prevent the engine from being started in a low oil or no oil condition. The Oil Sentry™ may not shut down a running engine before damage occurs. In some applications this switch may activate a warning signal. Read your equipment manual for more information.

The pressure switch is designed to make contact as the oil pressure decreases below 2-5 psi depending upon the application and switch speciﬁ ed.

On stationary or una ended applications (pumps, generators, etc.), the pressure switch can be used to ground the ignition module to stop the engine. On vehicular applications (lawn tractors, mowers, etc.) the pressure switch can only be used to activate a low oil warning light or signal.

NOTE: Make sure the oil level is checked BEFORE

™

EACH USE and is maintained up to the F mark on the dipstick. This includes engines equipped with Oil Sentry™.

Figure 6-9. Remote Oil Cooler.

Installation

The Oil Sentry™ pressure switch is installed into the breather cover. See Figure 6-10.

Figure 6-10. Location of Oil Sentry™ Switch.

6.4

Section 6

Lubrication System

On engines not equipped with Oil Sentry™ the installation hole is sealed with a 1/8-27 N.P.T.F. pipe plug.

To install the switch, follow these steps:

1. If no sealant is preapplied, apply pipe sealant

with Teﬂ on

or equivalent) to the threads of the switch.

2. Install the switch into the tapped hole in the breather cover. See Figure 6-9.

3. Torque the switch to 4.5 N·m (40 in. lb.).

4. A ach lead to switch terminal.

Testing the Switch

Compressed air, a pressure regulator, pressure gauge and a continuity tester are required to test the switch.

Normally Closed Switch

1. Connect the continuity tester across the blade terminal and the metal case of the switch. With 0 psi pressure applied to the switch, the tester should indicate continuity (switch closed).

(Loctite® 592™ PST® Thread Sealant

3. Gradually decrease the pressure through the

range of 2.0/5.0 psi. The tester should indicate a change to no continuity (switch open) down to 0 psi.

2. Gradually increase the pressure to the switch. As pressure increases through the range of

2.0/5.0 psi, the tester should indicate a change to no continuity (switch open). The switch should

remain open as the pressure is increased to 90 psi maximum.

3. Gradually decrease the pressure through the range of 2.0/5.0 psi. The tester should indicate a change to continuity (switch closed) down to 0 psi.

4. Replace the switch if it does not operate as speciﬁ ed.

Normally Open Switch

1. Connect the continuity tester across the blade terminal and the metal case of the switch. With 0 psi pressure applied to the switch, the tester should indicate no continuity (switch open).

2. Gradually increase the pressure to the switch. As pressure increases through the range of

2.0/5.0 psi, the tester should indicate a change to continuity (switch closed). The switch should

remain closed as the pressure is increased to 90 psi maximum.

6.5

Section 6 Lubrication System

6.6

Section 7

Electrical System and Components

Section 7

Electrical System and Components

This section covers the operation, service, and repair of the electrical system components. Systems and components covered in this section are:

• Spark Plugs

• Ba ery and Charging System

• Electric Starter

Spark Plugs

Engine misﬁ re or starting problems are o en caused by a spark plug that has improper gap or is in poor condition.

The engine is equipped with the following spark plugs:

Type: The standard spark plug is a Champion®

RC12YC (Kohler Part No. 12 132 02-S). RFI compliant engines use a Champion® XC12YC (Kohler 25 132 14-S) spark plug. A high-performance spark plug, Champion® Platinum 3071 (used on Pro Series engines, Kohler Part No. 25 132 12-S) is also available. Equivalent alternate brand plugs can also be used.

Gap: 0.76 mm (0.030 in.) Thread Size: 14 mm Reach: 19.1 mm (3/4 in.) Hex Size: 15.9 mm (5/8 in.)

Spark Plug Service

Remove the spark plugs a er every 200 hours of operation. Check their condition and either reset the gap or replace with new plugs as necessary. To service the plugs, perform the following steps:

1. Before removing a spark plug, clean the area

around the base of the plug to keep dirt and debris out of the engine.

NOTE: Do not clean spark plugs in a machine

using abrasive grit. Some grit could remain in the spark plug and enter the engine, causing extensive wear and damage.

3. Check the gap using a wire feeler gauge. Adjust

the gap to 0.76 mm (0.030 in.) by carefully bending the ground electrode. See Figure 7-1.

Wire Gauge

Spark Plug

Ground Electrode

Figure 7-1. Servicing Spark Plug.

4. Reinstall the spark plug into the cylinder head

and torque to 24.4-29.8 N·m (18-22  . lb.).

Inspection

Inspect each spark plug as it is removed from the cylinder head. The deposits on the tip are an indication of the general condition of the piston rings, valves, and fuel injection system.

0.76 mm

(0.030 in.) Gap

2. Remove the plug and check its condition. See

Inspection following this procedure. Replace the plug if necessary.

Normal and fouled plugs are shown in the following photos:

7.1

Section 7 Electrical System and Components

Normal: A plug taken from an engine operating under normal conditions will have light tan or gray colored deposits. If the center electrode is not worn, a plug in this condition could be set to the proper gap and reused.

Carbon Fouled: So , sooty, black deposits indicate incomplete combustion caused by a restricted air cleaner, over-rich fuel mixture, weak ignition, or poor compression.

Wet Fouled: A wet plug is caused by excess fuel or oil in the combustion chamber. Excess fuel could be caused by a restricted air cleaner or rich air/fuel ratio. Oil in the combustion chamber is usually caused by a restricted air cleaner, a breather problem, or worn piston rings, cylinder walls or valve guides.

Overheated: Chalky, white deposits indicate very high combustion temperatures. This condition is usually accompanied by excessive gap erosion. Lean air/fuel ratio, an intake air leak, or incorrect spark timing are normal causes for high combustion temperatures.

Worn: On a worn plug, the center electrode will be rounded and the gap will be greater than the speciﬁ ed gap. Replace a worn spark plug immediately.

7.2

Section 7

Electrical System and Components

Battery

General

A 12-volt ba ery with 400 cold cranking amps is generally recommended for starting in all conditions. A smaller capacity ba ery is o en suﬃ cient if an application is started only in warmer temperatures. Refer to the following table for minimum cold cranking amp (cca) capacities, based on anticipated ambient temperatures. The actual cold cranking requirement depends on engine size, application, and starting temperatures. The cranking requirements increase as temperatures decrease and ba ery capacity shrinks. Refer also to the operating instructions for the piece of equipment for speciﬁ c ba ery requirements.

Battery Size Recommendations

Temperature Ba ery Required

Above 32°F (0°C) 200 cca minimum

0°F to 32°F (-18°C to 0°C) 250 cca minimum

-5°F to 0°F (-21°C to -18°C) 300 cca minimum

-10°F (-23°C) or below 400 cca minimum

2. Keep the cables, terminals, and external surfaces of the ba ery clean. A build-up of corrosive acid or grime on the external surfaces can cause the ba ery to self-discharge. Self-discharge occurs rapidly when moisture is present.

3. Wash the cables, terminals, and external surfaces with a mild baking soda and water solution. Rinse thoroughly with clear water.

NOTE: Do not allow the baking soda solution

to enter the cells, as this will destroy the electrolyte.

Battery Test

To test the ba ery, you will need a DC voltmeter. Perform the following steps (see Figure 7-2):

1. Connect the voltmeter across the ba ery terminals.

2. Crank the engine. If the ba ery drops below 9 volts while cranking, the ba ery is too small, discharged, or faulty.

If the ba ery charge is not suﬃ cient to turn over the engine, recharge the ba ery.

Battery Maintenance

Regular maintenance is necessary to prolong ba ery life.

WARNING: Explosive Gas!

Ba eries produce explosive hydrogen gas while being charged. To prevent a ﬁ re or explosion, charge ba eries only in well ventilated areas. Keep sources of ignition away from the ba ery at all times. Keep ba eries out of the reach of children. Remove all jewelry when servicing ba eries.

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.

1. Regularly check the level of electrolyte. Add distilled water as necessary to maintain the recommended level.

NOTE: Do not overﬁ ll the ba ery. Poor

performance or early failure due to loss of electrolyte will result.

DC Voltmeter

Battery

Figure 7-2. Battery Voltage Test.

7.3

Section 7 Electrical System and Components

Battery Charging System

General

These engines are equipped with a 20 or 25 amp regulated charging system. See Figure 7-3 for the 20/25 amp charging system diagram.

NOTE: Observe the following guidelines to

avoid damage to the electrical system and components:

• Make sure the ba ery polarity is correct. A negative (-) ground system is used.

• Disconnect the rectiﬁ er-regulator plug and/ or the wiring harness plug before doing any electric welding on the equipment powered by the engine. Also, disconnect all other electrical accessories in common ground with the engine.

• Prevent the stator (AC) leads from touching or shorting while the engine is running. This could damage the stator.

Stator

The stator is mounted on the crankcase behind the ﬂ ywheel. Follow the procedures in Section 8 - Disassembly and Section 10 - Reassembly if stator replacement is necessary.

Figure 7-4. 20 Amp Stator and Rectiﬁ er-Regulator.

20/25 Amp Regulated Charging System

Fuse

Rectiﬁ er- Regulator

Battery

Connector Block

Starter

Figure 7-3. Wiring Diagram - 20/25 Amp Regulated Battery Charging System.

Flywheel

Stator

Assembly

7.4

Rectiﬁ er-Regulator

The rectiﬁ er-regulator is mounted on the blower housing. See Figure 7-5. To replace it, disconnect the plug(s), remove the two mounting screws, and ground wire or metal grounding strap.

NOTE: When installing the rectiﬁ er-regulator, take

note of the terminal markings and install the plug(s) accordingly.

Rectiﬁ er- Regulator

Section 7

Electrical System and Components

Ground

Lead

Red Lead

Black Leads

Figure 7-6. Connecting Leads to Rectiﬁ er- Regulator.

4. Plug the tester into the proper AC outlet/power supply for tester being used. Turn on the power switch. The POWER light should be illuminated and one of the four status lights may be lit as well. See Figure 7-7. This does not represent the condition of the part.

Figure 7-5. Rectiﬁ er-Regulator.

Testing of the rectiﬁ er-regulator may be performed as follows, using the Rectiﬁ er-Regulator Tester, (see Section 2).

NOTE: Disconnect all electrical connections a ached

to the rectiﬁ er-regulator. Testing may be performed with the rectiﬁ er-regulator mounted or loose. The ﬁ gures show the part removed from the engine for clarity. Repeat the applicable test procedure two or three times to determine the condition of the part.

1. Connect the tester ground lead (with spring clamp) to the body of the rectiﬁ er-regulator.

2. Connect the red lead from the tester to the middle terminal labeled B+.

3. Connect the two black leads from the tester to both of the outer AC terminals on the rectiﬁ er- regulator. See Figure 7-6.

Power Switch

Test Button

Figure 7-7. Testing the Rectiﬁ er-Regulator with a Tester.

5. Press the TEST bu on until a click is heard and

then release. See Figure 7-7. Momentarily one of the four status lights will illuminate indicating the partial condition of the part.

a. If the OK (green) light comes on the part is

good and may be used.

b. If any other light is displayed* the rectiﬁ er-

regulator is faulty and should not be used.

*NOTE: A ﬂ ashing LOW light can also occur as

a result of an inadequate ground lead connection. Make certain the connection location is clean and the clamp is secure.

7.5

Section 7 Electrical System and Components

Troubleshooting Guide

20/25 Amp Battery Charging Systems

When problems occur in keeping the ba ery charged or the ba ery charges at too high a rate, the problem can usually be found somewhere in the charging system or with the ba ery.

NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should

be made with the engine running at 3600 RPM - no load. The ba ery must be good and fully charged.

Problem Test Conclusion

No Charge

to Battery

1. Trace B+ lead from rectiﬁ er-regulator to key switch, or other accessible connection. Disconnect it from switch or connection. Connect an ammeter from loose end of B+ lead to positive terminal of ba ery. Connect DC voltmeter from loose end of B+ lead to negative terminal of ba ery. With engine running at 3600 RPM, read voltage on voltmeter.

If voltage is 13.8 volts or

more, place a minimum load of 5 amps* on ba ery to reduce voltage. Observe ammeter.

*NOTE: Turn on lights, if 60

wa s or more. Or place a 2.5 ohm, 100 wa resistor across ba ery terminals.

1. If voltage is 13.7-14.7 and charge rate increases when load is applied, the charging system is OK and ba ery was fully charged.

If voltage is less than 13.8 or charge rate does not increase

when load is applied, test rectiﬁ er-regulator for proper ground. Using an ohmmeter set to the Rx1 scale, check the resistance from the rectiﬁ er-regulator housing to the ba ery ground. Resistance should be less than 1 ohm. As an alternative, connect a jumper lead from rectiﬁ er-regulator housing to the ba ery ground and retest charging voltage. If charge voltage measures 13.7-14.7 volts, the charging system is functioning. If resistance is greater than 1 ohm or charge voltage is less than 13.7, then re-establish ground between the ground strap and mounting screw.

If voltage is less than 13.8 or charge rate does not increase

when load is applied, test stator (Tests 2 and 3).

If the voltage is low and does not increase, and there is no

charging/amperage output, disconnect and reconnect the rectiﬁ er-regulator plug and retest.

a. If the ammeter shows charge for a short time but then

drops back to zero, the rectiﬁ er-regulator is functioning correctly but the ba ery is faulty. Replace the ba ery.

7.6

2. Remove connector from rectiﬁ er-regulator. With engine running at 3600 RPM, measure AC voltage across stator leads using an AC voltmeter.

3a. With engine stopped,

measure the resistance across stator leads using an ohmmeter.

3b. With the engine stopped,

measure the resistance from each stator lead to ground using an ohmmeter.

b. If no amperage/charge rate appears during the retest, go

to step 2.

2. If voltage is 28 volts or more, stator is OK. Rectiﬁ er-regulator

is faulty. Replace the rectiﬁ er-regulator.

If voltage is less than 28 volts, stator is probably faulty and

should be replaced. Test stator further using an ohmmeter (Test 3).

3a. If resistance is 0.064/0.2 ohms, the stator is OK.

If the resistance is inﬁ nity ohms, stator is open. Replace

stator.

3b. If the resistance is inﬁ nity ohms (no continuity), the stator is

OK (not shorted to ground).

If resistance (or continuity) is measured, the stator leads are

shorted to ground. Replace stator.

Section 7

Electrical System and Components

Battery Continuously Charges at High Rate

1. Perform same test as step 1 above.

Fuses

This engine has three (3) blade type automotive fuses. Replacement fuses must have the same rating as the blown fuse. Use the fuse chart below to determine the correct fuse.

Wire Color Fuse Rating

2 Purple Wires 30-amp Fuse

1 Red Wire with Black Stripe 1 Red Wire with White Stripe

2 Red Wires 10-amp Fuse

To Replace a Fuse:

1. Shut engine oﬀ and remove key.

2. Locate the fuse holders.

3. Remove the fuse cover and pull out fuse.

10-amp Fuse

1. If the voltage is 14.7 volts or less the charging

system is OK. The ba ery is unable to hold a charge. Service ba ery or replace as necessary.

If voltage is more than 14.7 volts, the rectiﬁ er-

regulator is faulty. Replace rectiﬁ er-regulator.

Electric Starting Motors

These engines use solenoid shi starters.

Starting Motor Precautions

NOTE: Do not crank the engine continuously for

more than 10 seconds at a time. If the engine does not start, allow a 60-second cool-down period between starting a empts. Failure to follow these guidelines can burn out the starter motor.

NOTE: If the starter cranks the engine but does not

start the engine, the engine rotation must be allowed to come to a complete stop before a empting to restart the engine again. If the starter is engaged while the ﬂ ywheel is rotating, the starter pinion and ﬂ ywheel ring gear may clash, resulting in damage to the starter.

4. Inspect the fuse for a solid fusible link or a broken fusible link. Replace the fuse if the fusible link is broken. If you are not sure if the fusible link is broken, replace the fuse.

5. Insert the fuse into the fuse holder until it is seated properly. Install the fuse cover.

NOTE: If the starter does not crank the engine, shut

oﬀ the starter immediately. Do not make further a empts to start the engine until the condition is corrected.

NOTE: Do not drop the starter or strike the starter

frame. Doing so can damage the starter.

Starter Removal and Installation

Refer to the Disassembly and Reassembly Sections for starter removal and installation procedures.

7.7

Section 7 Electrical System and Components

Troubleshooting Guide - Staring Difﬁ culties

Problem Possible Fault Correction

1. Check the speciﬁ c gravity of ba ery. If low, recharge or replace ba ery as necessary.

1. Clean corroded connections and tighten loose connections.

2. Replace wires in poor condition and with frayed or broken insulation.

1. By-pass the switch or solenoid with a jumper wire. If starter cranks normally, replace the faulty components. Solenoid Shi Starters: Perform individual solenoid test procedure. See pages

7.16 and 7.17.

1. Check the speciﬁ c gravity of ba ery. If low, recharge or replace ba ery as necessary.

1. Check for excessively dirty or worn brushes and commutator. Clean using a coarse cloth (not emery cloth).

2. Replace brushes if excessively or unevenly worn.

1. Make sure the clutch or transmission is disengaged or placed in neutral. This is especially important on equipment with hydrostatic drive. The transmission must be exactly in neutral to prevent resistance which could keep the engine from starting.

2. Check for seized engine components such as the bearings, connecting rod, and piston.

Starter Does Not Energize

Starter Energizes but Turns Slowly

Battery

Wiring

Starter Switch or Solenoid

Battery

Brushes

Transmission or Engine

Solenoid Shift Electric Starters

Operation – Solenoid Shift Starter

When power is applied to the starter the electric solenoid moves the drive pinion out onto the drive sha and into mesh with the ﬂ ywheel ring gear. When the pinion reaches the end of the drive sha it rotates the ﬂ ywheel and cranks the engine.

When the engine starts and the start switch is released the starter solenoid is deactivated, the drive lever moves back, and the drive pinion moves out of mesh with the ring gear into the retracted position.

Collar

Ring Stop

Drive

Armature

Washer

Tube

Screw

Plunger

Spring Lever

Plate

Plug

Solenoid

Frame & Field

Brush Holder

Nut

CE Frame

Figure 7-8. Completed Delco-Remy Starter.

7.8

Screw

Bolt

Figure 7-9. Delco-Remy Starter.

Starter Disassembly

1. Remove the hex nut and disconnect the positive (+) brush lead/bracket from the solenoid terminal.

2. Remove the three screws securing the solenoid to the starter. See Figure 7-10.

Torx Head Screws

Section 7

Electrical System and Components

Figure 7-12. Removing Thru Bolts.

4. Remove the commutator end plate assembly, containing the brush holder, brushes, springs, and locking caps. Remove the thrust washer from inside the commutator end. See Figure 7-13.

Figure 7-10. Removing Solenoid Screws.

NOTE: Test procedure for checking starter solenoid

on pages 7.16 and 7.17.

Figure 7-11. Solenoid Removed from Starter.

3. Remove the two thru (larger) bolts. See Figure 7-12.

Figure 7-13. Removing Commutator End Plate Assembly.

5. Remove the frame from the armature and drive end cap. See Figure 7-14.

Figure 7-14. Starter Frame Removed.

7.9

Section 7 Electrical System and Components

6. Remove the rubber grommet and backing plate from the end cap. See Figure 7-15.

Figure 7-17. Retaining Ring Detail.

Figure 7-15. Rubber Grommet and Backing Plate.

7. Take out the drive lever and pull the armature out of the drive end cap. See Figure 7-16.

8. Remove the thrust washer from the armature sha . See Figure 7-16.

Figure 7-16. Armature and Lever Removed.

9. Push the stop collar down to expose the retaining ring. See Figure 7-17.

10. Remove the retainer from the armature sha . Save the stop collar. See Figure 7-18.

NOTE: Do not reuse the old retainer.

Figure 7-18. Removing Retaining Ring.

11. Remove the drive pinion assembly from the armature.

12. Clean the parts as required.

NOTE: Do not soak the armature or use solvent

when cleaning. Wipe clean using a so cloth, or use compressed air.

7.10

Inspection

Drive Pinion

Check and inspect the following areas:

a. The pinion teeth for abnormal wear or damage.

b. The surface between the pinion and the clutch

mechanism for nicks, or irregularities which could cause seal damage.

Section 7

Electrical System and Components

Commutator O.D.

c. Check the drive clutch by holding the clutch

housing and rotating the pinion. The pinion should rotate in one direction only.

Brushes and Springs

Inspect both the springs and brushes for wear, fatigue, or damage. Measure the length of each brush. The minimum length for each brush is 7.6 mm (0.300 in.). See Figure 7-19. Replace the brushes if they are worn undersize, or their condition is questionable.

Wear limit length:

7.6 mm (0.300 in.)

Mica Insulation

Figure 7-20. Commutator Mica Inspection.

2. Use an ohmmeter set to the Rx1 scale. Touch the probes between two diﬀ erent segments of the commutator, and check for continuity. See Figure 7-21. Test all the segments. Continuity must exist between all or the armature is bad.

Insulation Check

Armature Coil

Figure 7-21. Checking Armature.

Continuity Check

Figure 7-19. Checking Brushes.

Armature

1. Clean and inspect the commutator (outer surface). The mica insulation must be lower than the commutator bars (undercut) to ensure proper operation of the commutator. See Figure 7-20.

3. Check for continuity between the armature coil segments and the commutator segments. See Figure 7-21. There should be no continuity. If continuity exists between any two, the armature is bad.

4. Check the armature windings/insulation for shorting.

Shift Fork

Check that the shi fork is complete, and the pivot and contact areas are not excessively worn, cracked or broken.

7.11

Section 7 Electrical System and Components

Brush Replacement

The brushes and springs are serviced as a set (4). Use Kohler Brush and Spring Kit, if replacement is necessary.

1. Perform steps 1-5 in Starter Disassembly.

2. Remove the two screws securing the brush holder assembly to the end cap (plate). Note the orientation for reassembly later. See Figure 7-22. Discard the old brush holder assembly.

Figure 7-22. Removing Brush Holder.

Starter Service

Clean the drive lever and armature sha . Apply Kohler electric starter drive lubricant (see Section 2) (Versilube G322L or Mobil Temp SHC 32) to the lever and sha . Clean and check the other starter parts for wear or damage as required.

Starter Reassembly

1. Apply drive lubricant (see Section 2) to the armature sha splines. Install the drive pinion onto the armature sha .

2. Install and assemble the stop collar/retainer assembly. See Figure 7-24.

a. Install the stop collar down onto the armature

sha with the counter bore (recess) up.

b. Install a new retainer in the larger (rear)

groove of the armature sha . Squeeze with a pliers to compress it in the groove.

c. Slide the stop collar up and lock it into place,

so the recess surrounds the retainer in the groove. If necessary, rotate the pinion outward on the armature splines against the retainer to help seat the collar around the retainer.

3. Clean the component parts as required.

4. The new brushes and springs come preassembled in a brush holder with a protective sleeve that will also serve as an installation tool. See Figure 7-23.

Figure 7-23. Service Brush Kit.

5. Perform Steps 10-13 in the Starter Reassembly sequence. Installation must be done a er the armature, drive lever, and frame are installed, if the starter has been disassembled.

Figure 7-24. Installing Stop Collar and Retainer.

NOTE: Always use a new retainer. Do not reuse old

retainers, which have been removed.

7.12

Section 7

Electrical System and Components

3. Install the oﬀ set thrust (stop) washer so the

smaller oﬀ set of the washer faces the retainer/ collar. See Figure 7-25.

Figure 7-25. Installing Thrust Washer.

4. Apply a small amount of oil to the bearing in the drive end cap, and install the armature with the drive pinion.

5. Lubricate the fork end and center pivot of the drive lever with drive lubricant (see Section 2). Position the fork end into the space between the captured washer and the rear of the pinion.

7. Install the backing plate, followed by the rubber grommet, into the matching recess of the drive end cap. The molded recesses in the grommet should be out, matching and aligned with those in the end cap. See Figure 7-27.

Figure 7-27. Installing Backing Plate and Grommet.

8. Install the frame, with the small notch forward, onto the armature and drive end cap. Align the notch with the corresponding section in the rubber grommet. Install the drain tube in the rear cutout, if it was removed previously. See Figure 7-28.

6. Slide the armature into the drive end cap, and at the same time seat the drive lever into the housing.

NOTE: Correctly installed, the center pivot section

of the drive lever will be ﬂ ush or below the machined surface of the housing which receives the backup washer. See Figure 7-26.

Figure 7-26. Installing Armature and Pivot Lever.

Figure 7-28. Installing Frame and Drain Tube.

9. Install the ﬂ at thrust washer onto the commutator end of the armature sha . See Figure 7-29.

7.13

Section 7 Electrical System and Components

Figure 7-29. Installing Thrust Washer.

10. Starter reassembly when replacing the Brushes/

Brush Holder Assembly:

a. Hold the starter assembly vertically on the

end housing, and carefully position the assembled brush holder assembly, with the supplied protective tube, against the end of the commutator/armature. The mounting screw holes in the metal clips must be up/out. Slide the brush holder assembly down into place around the commutator, and install the positive (+) brush lead grommet in the cutout of the frame. See Figure 7-30. The protective tube may be saved and used for future servicing.

Figure 7-31. Removing Retaining Clips.

b. Position each of the brushes back in their slots

so they are ﬂ ush with the I.D. of the brush holder assembly. Insert the Brush Installation Tool with extension, or use the tube described above from a prior brush installation, through the brush holder assembly, so the holes in the metal mounting clips are up/out.

c. Install the brush springs and snap on the four

retainer caps. See Figure 7-32.

Figure 7-30. Installing Brush Holder Assembly with Supplied Tube.

Starter reassembly when not replacing the Brushes/ Brush Holder Assembly:

a. Carefully unhook the retaining caps from over

each of the brush assemblies. Do not lose the springs. See Figure 7-31.

7.14

Figure 7-32. Brush Installation Tool with Extension.

d. Hold the starter assembly vertically on the

end housing, and carefully place the tool (with extension) and assembled original brush holder assembly onto the end of the armature sha . Slide the brush holder assembly down into place around the commutator, install the positive (+) brush lead grommet in the cutout of the frame. See Figure 7-33.

Section 7

Electrical System and Components

Figure 7-33. Installing Brush Holder Assembly using Tool with Extension.

11. Install the end cap onto the armature and frame, aligning the thin raised rib in the end cap with the corresponding slot in the grommet of the positive (+) brush lead.

12. Install the two thru bolts, and the two brush holder mounting screws. Torque the thru bolts to

5.6-9.0 N·m (49-79 in. lb.). Torque the brush holder mounting screws to 2.5-3.3 N·m (22-29 in. lb.). See Figures 7-34 and 7-35.

Figure 7-35. Torquing Brush Holder Screws.

13. Hook the plunger behind the upper end of the drive lever, and install the spring into the solenoid. Insert the three mounting screws through the holes in the drive end cap. Use these to hold the solenoid gasket in position, then mount the solenoid. Torque the screws to

4.0-6.0 N·m (35-53 in. lb.).

14. Connect the positive (+) brush lead/bracket to the solenoid and secure with the hex nut. Torque the nut to 8-11 N·m (71-97 in. lb.). Do not overtighten. See Figure 7-36.

Figure 7-34. Torquing Thru Bolts.

Figure 7-36. Positive (+) Brush Lead Connection.

7.15

Section 7 Electrical System and Components

Solenoid Test Procedure

Solenoid Shift Style Starters

Disconnect all leads from the solenoid including the positive brush lead a ached to the lower stud terminal. Remove the mounting hardware and separate the solenoid from the starter for testing.

Test 1. Solenoid Pull-In Coil/Plunger Actuation.

Use a 12 volt power supply and two test leads. Connect one lead to the ﬂ at spade START terminal on the solenoid. Momentarily* connect the other lead to the lower large post terminal. See Figure 7-37. When the connection is made the solenoid should energize (audible click), and the plunger retract. Repeat the test several times. If the solenoid fails to activate, it should be replaced.

*NOTE: DO NOT leave the 12 volt test leads

connected to the solenoid for any time over what is necessary for performing each of the individual tests. Internal damage to the solenoid may otherwise occur.

12 volt Test Leads Momentary Connection Only

VOM Leads

Figure 7-38. Testing Pull-In Coil/Solenoid Contact Continuity.

Test 3. Solenoid Hold-In Coil Function Test.

Connect one 12 volt test lead to the ﬂ at spade START terminal on the solenoid, and the other lead to the body or mounting surface of the solenoid. Then, manually push the plunger in and check if the Hold-In coil holds the plunger retracted. See Figure 7-39.

12 volt Test Leads Momentary Connection Only

Figure 7-37. Testing Pull-In Coil/Plunger Actuation.

Test 2. Solenoid Pull-In Coil/Contact Continuity.

Use an ohmmeter set to the audible or Rx2K scale, and connect the two ohmmeter leads to the two large post terminals. Perform the preceding test (1) and check for continuity. See Figure 7-38. The ohmmeter should indicate continuity, if no continuity is indicated the solenoid should be replaced. Repeat test several times to conﬁ rm condition.

Do not allow the test leads to remain connected to the solenoid for a prolonged period of time. If the plunger fails to stay retracted, the solenoid should be replaced.

Manually Push Plunger “In”

12 volt Test Leads Connect Only Long Enough to Test

Figure 7-39. Testing Hold-In Coil/Function Test.

7.16

Test 4. Solenoid Hold-In Coil/Contact Continuity.

Use an ohmmeter set to the audible or Rx2K scale, and connect the two ohmmeter leads to the two large post terminals. Perform the preceding test (3) and check for continuity. See Figure 7-40. The meter should indicate continuity, if no continuity is indicated the solenoid should be replaced. Repeat test several times to conﬁ rm condition.

Section 7

Electrical System and Components

VOM Meter

Plunger Pushed “In”

12 volt Test Leads

Figure 7-40. Testing Hold-In Coil/Solenoid Contact Continuity.

Leads

7.17

Section 7 Electrical System and Components

7.18

Section 8

Disassembly

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.

General

Clean all parts thoroughly 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.

16. Remove oil temperature sensor.

17. Remove inner baﬄ es and breather cover.

18. Remove valve covers.

19. Remove cranksha position sensor.

20. Remove manifold absolute pressure (MAP) sensor.

21. Remove fuel injectors.

22. Remove intake manifold.

23. Remove spark plugs.

24. Remove cylinder heads and hydraulic li ers.

25. Remove fan and ﬂ ywheel.

26. Remove stator and backing plate.

27. Remove closure plate assembly.

28. Remove camsha .

29. Remove governor cross sha .

30. Remove connecting rods with pistons and rings.

31. Remove cranksha .

32. Remove ﬂ ywheel end oil seal.

Disconnect Spark Plug Leads

1. Disconnect the leads from the spark plugs. See Figure 8-1.

NOTE: Pull on boot only, to prevent damage to

spark plug lead.

Typical Disassembly Sequence

The following sequence is suggested for complete engine disassembly. The sequence can be varied to accommodate options or special equipment.

1. Disconnect spark plug leads.

2. Shut oﬀ fuel supply.

3. Drain oil from crankcase and remove oil ﬁ lter.

4. Remove oil cooler.

5. Remove muﬄ er.

6. Remove air cleaner assembly.

7. Remove thro le control panel.

8. Remove external governor controls.

9. Remove li fuel pump and fuel pump module.

10. Remove thro le body.

11. Remove Electronic Control Unit (ECU).

12. Remove ECU bracket and electric starter motor.

13. Remove grass screen.

14. Remove outer baﬄ es and blower housing.

15. Remove Oil Sentry™.

Figure 8-1. Disconnect Both Spark Plug Leads.

8.1

Section 8 Disassembly

Shut Off Fuel Supply

Drain Oil from Crankcase and Remove Oil Filter

1. Remove the oil ﬁ ll cap, dipstick, and one of the oil drain plugs. See Figures 8-2 and 8-3.

NOTE: Some models are equipped with an oil drain

valve.

Figure 8-4. Removing Oil Filter.

Remove Oil Cooler

1. Use an 8 mm Allen wrench to remove the oil ﬁ lter threaded nipple. See Figure 8-5.

Figure 8-2. Removing Dipstick/Oil Fill Cap from Tube.

Figure 8-3. Removing Oil Drain Plug.

2. Allow ample time for the oil to drain from the crankcase and oil ﬁ lter.

3. Remove and discard the oil ﬁ lter. See Figure 8-4.

Threaded Nipple

Figure 8-5. Oil Filter Threaded Nipple.

2. Separate the ﬁ lter adapter from the closure plate, leaving the oil lines a ached. Remove the two hex ﬂ ange screws mounting the oil cooler to the blower housing, then remove the cooler, lines, and ﬁ lter adapter as an assembly. See Figure 8-6.

8.2

Figure 8-6. Removing Oil Cooler.

Section 8

Hex Flange Nuts

Disassembly

Remove Mufﬂ er

1. Remove the exhaust system and a aching hardware from the engine. On engines equipped with a port liner, remove it now.

2. Remove the oxygen sensor and disconnect the connector from the wire harness.

Remove Air Cleaner Assembly

Heavy Duty Air Cleaner

1. Remove the three hex ﬂ ange nuts securing the air cleaner assembly to the thro le body. See Figure 8-7.

Hex Flange Nuts

Low-Proﬁ le Air Cleaner (Optional)

1. Loosen the retaining knob and remove the cover.

2. Remove the wing nut from the element cover.

3. Remove the element cover, the air cleaner element with precleaner, and the stud seal. See Figure 8-9.

Precleaner Element

Air Cleaner Element

Stud Seal

Figure 8-9. Removing Air Cleaner Element, Precleaner, and Stud Seal.

Figure 8-7. Heavy Duty Air Cleaner Mounting Fastener Location.

2. Remove the two hex ﬂ ange screws securing the air cleaner assembly to the air cleaner bracket and remove the air cleaner assembly. See Figure 8-8.

Figure 8-8. Air Cleaner Bracket Mounting Fastener Location.

4. Remove the three hex ﬂ ange nuts. See Figure 8-10.

5. Remove the two hex ﬂ ange screws securing the base and then remove the base. See Figures 8-10 and 8-11.

Hex Flange Screws

Figure 8-10. Removing Air Cleaner Base Nuts.

8.3

Section 8

Throttle Linkage Spring

Throttle Linkage

Throttle Linkage Bushing

Remove Hex Flange Screws

Disassembly

Figure 8-11. Removing Air Cleaner Base.

Remove Throttle Control Panel

1. Disconnect the thro le control cable.

2. Disconnect the thro le linkage spring. Remove the thro le linkage bushing and thro le linkage from the governor lever. See Figure 8-13.

Throttle Linkage

Throttle Linkage Spring

Figure 8-14. Disconnecting Throttle Linkage Spring.

Throttle Linkage Bushing

2. Remove the 4 hex ﬂ ange screws securing the thro le control panel and remove the panel from the blower housing. See Figure 8-12.

Remove Hex Flange Screws

Figure 8-12. Remove Throttle Control Panel.

Remove External Governor Controls

1. Disconnect the governor spring a aching the governor lever to the thro le actuator lever. See Figure 8-12.

5. Loosen the hex ﬂ ange nut and remove the governor lever from the cross sha . See Figure 8-14.

Figure 8-15. Removing Governor Lever.

Remove Lift Fuel Pump and Fuel Pump Module

WARNING

Explosive Fuel can cause ﬁ res and severe burns.

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

Figure 8-13. Disconnect Governor Spring.

8.4

Explosive Fuel!

Pulse Pump

Inlet Fuel Line

In-Line Filter (Tank to Pulse Pump)

Pulse Pump Bracket

Pump Outlet

Mounting Screws

Pump Assembly

Pump Inlet

WARNING

Explosive Fuel can cause ﬁ res and severe burns.

Fuel systems ALWAYS remains under HIGH PRESSURE.

Fuel Fire and Burns!

Pulse Style Pumps

1. Disconnect the fuel line at the in-line fuel ﬁ lter on the tank to pulse pump line. See Figure 8-16.

Pulse Pump

Section 8

Disassembly

3. Remove the two hex ﬂ ange screws securing the fuel pump to the bracket on the blower housing. See Figure 8-18

Mounting Screws

Pulse Pump Bracket

Figure 8-18. Fuel Pump Mounting Screw Locations.

4. Note or mark the orientation of the fuel pump, then remove the fuel pump with lines a ached.

Inlet Fuel Line

In-Line Filter (Tank to Pulse Pump)

Figure 8-16. Fuel Inlet Line Location.

2. Disconnect the pulse (vacuum) line from the crankcase. See Figure 8-17.

Mechanical Style Pumps

The mechanical style fuel pump is part of the valve cover assembly. See Figure 8-19.

Pump Outlet

Pump Assembly

Pump Inlet

Figure 8-19. Mechanical Style Fuel Pump.

1. Disconnect the fuel lines at the pump outlet and the in-line fuel ﬁ lter. See Figure 8-19.

2. The fuel pump will be removed with the valve cover. Refer to the valve cover removal procedure.

Figure 8-17. Disconnecting Pulse Line from Crankcase.

Remove Fuel Pump Module

1. Remove the three screws securing the fuel pump module.

2. Using a side cu er or similar tool, cut the Oetiker clamp to remove the inlet fuel line. A new Oetiker clamp will need to be used for reassembly. See Figure 8-20.

8.5

Section 8

Grey Release Tab

Release Button

Disassembly

Release Button

Figure 8-20. Remove Inlet Fuel Line and Oetiker Clamp.

3. Disconnect the yellow electrical connector by pulling up on the grey tab to release. See Figure 8-21.

Grey Release Tab

Figure 8-21. Disconnect Electrical Connector.

4. Wrap a shop towel completely around the high pressure fuel line connector.

Figure 8-22. Slowly Pull Connector.

NOTE: Figure 8-22 depicts removing the connector

without a shop towel wrapped around it for instructional purposes only.

6. Disconnect the vent hose from the top of the fuel pump module.

7. Remove the screws securing the fuel pump module baﬄ e which the pump was mounted to.

Remove Throttle Body

1. Disconnect the breather tube from the thro le body. See Figure 8-23.

5. 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. See Figure 8-22.

8.6

Figure 8-23. Disconnecting the Breather Tube.

2. Disconnect the intake air temperature sensor from the thro le body. See Figure 8-24.

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

Specifications and Main Features

Frequently Asked Questions

User Manual