Generator runs but controller displays 'Underspeed' or 'Low Frequency'; unit may shut down or fail to transfer.

Safety First: Turn OFF the generator breaker before testing. Avoid adjusting governor settings beyond minor linkage checks unless you are trained.

• 1. Verify no excessive load: Ensure the generator breaker is OFF and the transfer switch is not connected so the engine runs unloaded during diagnosis.
• 2. Inspect air filter and intake: Remove the air filter cover and check for a clogged or oil-soaked filter. Replace if dirty to restore airflow.
• 3. Check fuel supply and pressure: Confirm LP tank level or NG supply is adequate. Make sure all gas valves are fully open. If you have a manometer, verify fuel pressure at the generator gas inlet matches GE specifications.
• 4. Examine governor linkage: With engine off, move the governor arm and throttle. Clean any rust or debris and ensure the linkage is not binding. Do not change factory governor adjustment screws.
• 5. Inspect speed sensor wiring: Confirm the engine speed sensor connector is tight and wiring is intact. A weak or intermittent signal can cause false underspeed alarms.
• 6. Clear alarm and retest: Cycle the controller OFF then AUTO to clear the Underspeed alarm and run a manual test. If frequency remains low, professional adjustment of the governor or fuel system is recommended.