Kohler CH940 - Service Manual

Questions and Answers

A
awiseAug 20, 2025
How to fix Kohler Engine that starts but does not keep running?
- J
  jessicabergAug 20, 2025
  If your Kohler engine starts but doesn't keep running, the issue might stem from a restricted fuel tank cap vent; clear or replace the cap. Another possibility is poor fuel quality, or dirt/water in the fuel system, so replace the fuel and clean the fuel system. Also, check for faulty or misadjusted choke or throttle controls and adjust them as needed. Loose wires or connections that short the kill terminal of the ignition module to ground can also cause this, so repair any loose wires or connections. Other potential causes include a faulty cylinder head gasket (replace it), a faulty carburetor (repair or replace it), or an intake system leak (repair the leak).
M
Maurice DavisAug 23, 2025
How to fix Kohler CH940 Engine will not crank?
- K
  kennethbellAug 23, 2025
  If your Kohler engine will not crank, several issues could be preventing it. Ensure the PTO drive is disengaged. Check the battery; it may be discharged and need to be charged or replaced. Also, verify that the safety interlock switch is disengaged. Inspect for loose or faulty wires or connections and repair them. Other potential causes include a faulty key switch or ignition switch (replace it), a faulty electric starter or solenoid (replace it), or seized internal engine components (inspect and repair them).
W
Wesley RobinsonAug 26, 2025
How to resolve Kohler CH940 Engine starts hard?
- K
  Karen BoyleAug 26, 2025
  If your Kohler engine starts hard, several factors could be contributing. Ensure the PTO drive is disengaged. Check for dirt or water in the fuel system; if present, replace the fuel and clean the fuel system. A clogged fuel line could also be the problem, so clear it. Additionally, inspect for loose or faulty wires or connections and repair them. Other potential causes include faulty or misadjusted choke or throttle controls (adjust them), faulty spark plugs (replace them), low compression (check and correct compression levels), a weak spark (diagnose and fix the ignition system), a fuel pump malfunction (repair or replace it), or an overheated engine due to restricted cooling/air circulation (restore cooling/air circulation).
B
Brooke CastilloAug 28, 2025
How to troubleshoot Kohler CH940 Engine will not idle?
- C
  christinamartinAug 28, 2025
  If your Kohler engine won't idle, several issues could be the reason. Check for dirt or water in the fuel system, and replace the fuel and clean the fuel system if necessary. Stale fuel and/or gum in the carburetor could also be the cause, so replace the stale fuel and clean the carburetor. Other potential causes include faulty spark plugs (replace them), inadequate fuel supply (check and restore adequate fuel supply), improperly set idle fuel adjusting needles (adjust them), an improperly set idle speed adjusting screw (adjust it), low compression (check and correct compression levels), a restricted fuel tank cap vent (clear or replace it), or an overheated engine due to a cooling system/air circulation problem (restore the cooling system and air circulation).
S
Scott WilliamsAug 31, 2025
What causes Kohler CH940 to use excessive amount of oil?
- A
  Amber CollierAug 31, 2025
  If your Kohler engine uses an excessive amount of oil, it could be due to several reasons. Using the incorrect oil viscosity/type might be the cause, so use the correct oil viscosity/type. A clogged, broken, or inoperative crankcase breather could also be responsible; repair or replace it. Other potential causes include worn or broken piston rings (replace them), a worn cylinder bore (repair or replace it), worn valve stems/valve guides (replace them), an overfilled crankcase (remove excess oil), or a blown head gasket/overheating (replace the blown head gasket and check for overheating).
P
Paul BryantSep 3, 2025
What to do if Kohler Engine loses power?
- K
  Kenneth PooleSep 3, 2025
  If your Kohler engine is losing power, several factors could be responsible. Begin by checking the crankcase oil level; add oil if it's low or remove excess if it's high. Ensure the air cleaner element is clean; if dirty, clean or replace it. Inspect the fuel system for dirt or water, and replace the fuel and clean the system if necessary. Other potential causes include excessive engine load (reduce it), overheating (check for overheating issues), faulty spark plugs (replace them), low compression (check and correct compression levels), exhaust restrictions (clear them), a low battery (charge or replace it), or an incorrect governor setting (adjust it).
W
wwrightSep 5, 2025
What to do if Kohler CH940 overheats?
- J
  Jennifer RoachSep 5, 2025
  If your Kohler engine is overheating, several factors could be the cause. Start by checking the air intake/grass screen, cooling fins, or cooling shrouds for clogs and clean them if necessary. Other potential causes include excessive engine load (reduce it), low crankcase oil level (add oil), high crankcase oil level (remove excess oil), a faulty carburetor (repair or replace it), or a lean fuel mixture (adjust to correct fuel mixture).
C
Charles DavisSep 8, 2025
Why does my Kohler Engine knock?
- E
  Ernest JonesSep 8, 2025
  If your Kohler engine is knocking, it could be due to several reasons. Excessive engine load might be the cause, so reduce it. Check the crankcase oil level and add oil if it's low. Old or improper fuel could also be the culprit, so replace it with proper fuel. Other potential causes include internal wear or damage (inspect and repair internal components), hydraulic lifter malfunction (repair or replace hydraulic lifters), the quality of fuel (replace with high-quality fuel), or using the incorrect grade of oil (use the correct grade of oil).
S
Stephanie BriggsSep 12, 2025
What causes Kohler Engine to run but miss?
- M
  Morgan EvansSep 12, 2025
  If your Kohler engine runs but misses, several factors could be responsible. Start by checking for dirt or water in the fuel system and replace the fuel and clean the system if necessary. Ensure the spark plug lead is connected. Poor fuel quality could also be the issue, so replace it with high-quality fuel. Other potential causes include faulty spark plugs (replace them), loose wires or connections that intermittently ground the ignition kill circuit (repair them), an overheated engine (check for overheating issues), a faulty ignition module or incorrect air gap (repair or replace the ignition module and adjust the air gap), or an incorrectly adjusted carburetor (adjust it).
J
John LamSep 14, 2025
Why Kohler CH940 Engine has oil leaks from oil seals, gaskets?
- B
  bchaseSep 14, 2025
  If your Kohler engine has oil leaks from the oil seals and gaskets, one potential reason is a clogged, broken, or inoperative crankcase breather; repair or replace it. Loose or improperly torqued fasteners could also be the cause; tighten or replace them. Additionally, check for piston blowby or leaky valves and repair them. A restricted exhaust could also contribute to this issue, so clear any exhaust restrictions.

Kohler CH940 Specifications

General

Brand	Kohler
Model	CH940
Category	Engine
Language	English

Summary

Section 1 Safety and General Information

Safety Precautions

Ensures safe operation by following listed statements and understanding their meaning.

Engine Identification Numbers

Details on Model, Spec, Serial Numbers for part ordering and communication.

Oil Recommendations

Guidance on using the proper type, weight, and checking of engine oil.

Fuel Recommendations

Advice on purchasing, storing, and using gasoline for engine operation.

Periodic Maintenance Instructions

Schedule of required maintenance procedures based on frequency.

General Specifications

Technical specifications including power, bore, stroke, displacement, and torques.

General Torque Values

Metric and English fastener torque recommendations for standard applications.

Section 2 Tools & Aids

Separate Tool Suppliers

Contact information for Kohler Tools, SE Tools, and Design Technology Inc.

Aids

List of lubricants, sealants, and other aids with their source/part numbers.

Special Tools You Can Make

Instructions for fabricating a flywheel holding tool and rocker arm/crankshaft tool.

Section 3 Troubleshooting

Cleaning the Engine

Procedure for thoroughly cleaning the engine before disassembling or operating.

Crankcase Vacuum Test

Testing crankcase vacuum using a manometer or vacuum gauge.

Compression Test

Performing a compression test on a warm engine for engine condition.

Section 4 Air Cleaner and Air Intake System

Air Cleaners

General description of the heavy-duty style air cleaner system.

Air Intake;Cooling System

Ensuring proper cooling by keeping engine surfaces clean.

Section 5 Fuel System and Governor

Fuel Recommendations

Guidelines for purchasing, storing, and using gasoline.

Carburetor

General information on the Keihin BK two-barrel carburetor.

Carburetor Adjustments

Procedures for adjusting carburetor settings like low idle speed and fuel mixture.

Adjusting Governor

Steps for setting governor lever, idle speed, and high speed RPM.

Section 6 Lubrication System

Oil Recommendations

Guidance on selecting and using the correct type and viscosity of engine oil.

Checking Oil Level

Procedure for checking the engine's oil level.

Changing Oil and Oil Filter

Steps for changing the engine oil and replacing the oil filter.

Service Oil Cooler

Instructions for inspecting and cleaning the engine's oil cooler.

Oil Sentry

Information on the optional oil pressure monitor switch.

Section 7 Electrical System and Components

Spark Plugs

Information on spark plug type, gap, service, and inspection.

Battery and Charging System

Details on battery requirements, maintenance, testing, and charging systems.

Electric Starter

Information on starter motors, precautions, and troubleshooting.

Electronic CD Ignition System

Operation and troubleshooting of the capacitive discharge ignition system.

Troubleshooting Guide - Starting Difficulties

Diagnosing issues when the starter does not energize or turns slowly.

Section 8 Disassembly

Typical Disassembly Sequence

Suggested sequence for complete engine disassembly.

Remove Carburetor

Procedure for disconnecting and removing the carburetor assembly.

Remove Cylinder Heads and Hydraulic Lifters

Steps for removing cylinder heads, push rods, and hydraulic lifters.

Remove Crankshaft

Procedure for carefully removing the crankshaft from the crankcase.

Section 9 Inspection and Reconditioning

Camshaft

Inspection of camshaft lobes, gear, and teeth for wear or damage.

Crankshaft

Inspection of crankshaft gear teeth, bearing surfaces, and keyways.

Crankcase

Inspection of gasket surfaces, main bearings, and cylinder bore condition.

Pistons and Rings

Inspection for piston and ring damage, wear, and proper installation.

Section 10 Reassembly

Typical Reassembly Sequence

Suggested sequence for complete engine reassembly.

Install Connecting Rods with Pistons and Rings

Procedure for installing connecting rods, pistons, and rings correctly.

Assemble Cylinder Heads

Steps for assembling cylinder heads with valves and related components.

Testing the Engine

Recommendations for operating the engine on a test stand before installation.

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