Generator cranks but will not start; no error code displayed on the Firman controller.

Safety first: Turn OFF the generator and disconnect battery negative. Work in a ventilated area away from flames.

• Verify fuel and valves: Check that the fuel tank has fresh fuel and that all fuel shutoff valves are open. For NG/LP models, confirm gas supply and regulator operation.
• Inspect spark plugs: Remove spark plugs and inspect electrodes. Clean or replace if fouled, worn, or wet with fuel. Set gap to Firman specification.
• Check for spark: With the plug grounded to the engine block, crank the engine and look for a strong blue spark. If weak or absent, test the ignition coil and replace if necessary.
• Drain stale fuel: If fuel is older than 3–6 months, drain the tank and carburetor bowl, then refill with fresh fuel.

After addressing fuel and ignition, reconnect the battery and attempt a start. If the engine still will not start and no code appears, further diagnosis of compression and timing is required.