Kohler M20 Engine

No generator set in our catalog cites this exact engine designation yet; its specifications and fault codes are documented here.

How to read your Kohler engine serial & model number →

Fault codes

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

• Will not carry load or runs rough
  Cause: Fuel line restriction; Vent in fuel tank cap obstructed (gasoline fuel); Dirty fuel filter (gasoline fuel only); Improper type of fuel; Defective fuel pump; Governor not properly adjusted or defective; Carburetor not adjusted or defective; Defective ignition module; Defective/misadjusted spark plug; Carburetor choke; Fuel leak; Valves not sealing; improper valve clearance; Excessive carbon buildup; Fuel vapor lock {hot engine only}
  Fix: Inspect fuel lines and tank.; Clean cap in solvent, blow dry; Replace fuel filter; Use specified type of fuel; Check fuel pump pressure is 2-3.5 psi (14-24 kPa); Check speed using tachometer or frequency meter; Check and/or adjust; Test and/or replace; Regap or replace; Test and/or replace; Tighten fittings; Compression test; Adjust proper valve clearance; Clean cylinder head; Reroute fuel lines away from heat.
• Unit is noisy
  Cause: Exhaust system leak; Broken or damaged vibromounts; Loose or vibrating sheet metal/housing; inadequate compartment clearances; Exhaust piping or air inlets/outlets not securely installed; No compartment sound insulation; Excessive vibration—engine/generator
  Fix: Check and replace as necessary; Check and replace as necessary; Retighten screws; Check clearances; Inspect for loose parts; Install fireproof insulation; Check rotor, crankshaft, bearing, etc. (Disassembly of engine and/or generator may be required)
• Starter does not work properly
  Cause: Loose or corroded connections; Low battery output; Defective starter solenoid; Defective start/stop switch; Defective wiring; Defective starter
  Fix: Clean and tighten loose connections; Check electrolyte level and specific gravity (batteries with filler caps only); Check starter solenoid. Replace starter solenoid, as necessary; Replace switch; Check wiring; Replace starter
• Press start switch (Local or remote) Does engine crank?
  Fix: No: Is LED2 lit? Yes: Is 15-amp controller fuse okay? No: Replace circuit board (Defective K3 relay or K1 normally open contact)
• Overheats
  Cause: Improper cooling; Air cleaner clogged
  Fix: Check cooling system air flow; Clean or replace element
• Operates erratically
  Cause: Air cleaner clogged; Stale or bad fuel; Governor not properly adjusted or defective (Engine not operating at rated RPM); Fuel line restriction; Faulty spark plug(s); Carburetor adjustment wrong
  Fix: Clean or replace element; Replace spark plug(s); Adjust carburetor
• Low Oil Pressure Shutdown LOP
• Lacks power
  Cause: Governor not properly adjusted or defective (Engine not operating at rated RPM); Air cleaner clogged; Improper cooling; Engine overloaded; Stale or bad fuel; Fuel line restriction; Dirty fuel filter (gasoline fuel only); Carburetor adjustment wrong; Choke misadjusted or defective; Carbon buildup; Faulty spark plug(s); Defective ignition module
  Fix: Check engine speed using frequency meter or tachometer.; Clean or replace element; Check air flow cooling system; Reduce electrical load; Replace; Check fuel lines and tank; Replace fuel fitter; Adjust carburetor; Check and/or adjust; Clean cylinder heads; Replace spark plug(s); Test and/or replace coil
• Is there AC output when start button is held and unit is running?
  Fix: No: Is there battery voltage at brushes? (Check wiring) No: Replace controller circuit board
• Is the generator battery dead or low?
  Cause: No
  Fix: Is the battery in good condition and are the connections clean? Yes
• Is engine difficult to start?
  Cause: No
  Fix: Is fuel stale or contaminated? No Is air intake restricted? No Is carburetor or choke out of adjustment? No is there sufficient ignition spark? No Engine problem, see Engine Service Manual (TP-2204)
• Does the unit overspeed?
  Cause: Yes
  Fix: See Fuel System see Governor System
• Does the unit lose spark to the cylinders?
  Cause: Yes
  Fix: See Ignition System
• Does the unit lose fuel or is fuel depleted?
  Cause: Yes
  Fix: See Ignition System
• Does the unit lose AC output before unit shuts down?
  Cause: No

Compiled from service & troubleshooting documentation across every generator set that uses the Kohler M20.

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.