Controller displays “Overcrank” after multiple failed start attempts; engine cranks but does not start.

Safety first: Set the generator to OFF, open the main breaker, and disconnect battery negative. Shut off the gas supply at the manual shutoff valve before working on fuel components.

• Check fuel supply: Verify the gas shutoff valve to the generator is fully open. For LP systems, ensure the tank is not empty and that the regulator is not iced. For natural gas, confirm service is active and that other gas appliances work.
• Inspect gas line and regulator: On Kohler gaseous units (e.g., 14RESA, 20RESC), inspect the external gas regulator and the engine-mounted demand regulator for damage or icing. Ensure inlet pressure meets Kohler specifications (typically 5–14 in. w.c. depending on model).
• Check air filter: Remove and inspect the air filter element. Replace if heavily clogged, as this can cause rich mixture and no-start.
• Inspect spark plugs: Remove spark plugs and inspect for fouling, cracks, or excessive gap. Clean or replace with Kohler-specified plugs and set correct gap.
• Check ignition connections: Inspect ignition coil connectors, plug wires, and engine harness for loose or damaged wiring. Reseat connectors to the controller (ADC/RDC) and engine sensors.
• Clear fault and test: Restore gas supply, reconnect battery, set controller to AUTO, clear the Overcrank fault, and initiate a manual start. Listen for fuel solenoid click and observe exhaust for signs of firing.

If the engine still will not start, further diagnosis of fuel pressure, injector (on diesel), or crankshaft position sensor should be performed by a qualified technician with proper test equipment.