Kohler M18 Engine Engine

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

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.; NOTE: Hz x 120/ No. of rotor poles=rpm; (Example: 60 x 120/4=1800); 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.
• While the unit is cranking, is 12 vde present across P1-5(+) to P1-12(-)?
  Cause: No
  Fix: Replace control board
• 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 board K3 normally open e Check condition/connections of K3 relay or K1 u Replace circuit board (Defective K3 relay)
• Overheats
  Cause: Improper cooling; Air cleaner clogged; Carburetor adjusted too lean; Faulty spark plug(s)
  Fix: Check cooling system air flow; Clean or replace element; Adjust carburetor; Replace spark plug(s)
• 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; Check engine speed using frequency meter or tachometer.; NOTE: For 60 Hz-1800 RPM; For 50 Hz-1500 RPM; Inspect fuel lines and tank. Check fuel pump pressure of 2-3.5 psi (14-24 kPa); 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.; NOTE: For 60 Hz-1800 RPM; For 50 Hz-1500 RPM; 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 there 12 vde at P4-4?
  Cause: No
  Fix: Check wire #71 to control board
• Is there 12 vde at P1-4 while trying to start?
  Fix: See / Replace control board
• Is the engine difficult to start?
  Cause: No
  Fix: Is fuel stale or contaminated? / Is air intake restricted? / Is carburetor or choke out of adjustment? / Is there sufficient ignition spark?
• Is P4-18 battery grounded?
  Fix: Check wire N in the controller
• Is P1-9 grounded?
  Fix: Check N wire to ground stud in controller

Compiled from service & troubleshooting documentation across every generator set that uses the Kohler M18.

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.