Generator starts then immediately shuts down with OVERSPEED or ENGINE OVERSPEED alarm.

Safety first: Turn OFF the generator, disconnect battery negative, and prevent automatic start. Overspeed conditions can be dangerous; do not bypass safety circuits.

Steps:

• Inspect throttle and governor linkage: Open the engine compartment on the Gillette generator. Manually move the throttle lever and governor linkage; it should move smoothly and return by spring tension. Lubricate pivot points lightly if sticking.
• Check electronic governor actuator: On electronically governed models, inspect the actuator wiring harness and connector. Look for loose pins, chafed wires, or oil contamination. Repair as needed.
• Engine speed sensor: Verify the magnetic pickup or Hall-effect speed sensor at the flywheel is secure and not contacting the ring gear. Clean metal shavings from the tip and ensure proper gap.
• Controller settings: Confirm that the rated frequency and speed parameters in the Gillette digital controller match the generator nameplate (e.g., 60 Hz, 1800 RPM). Incorrect settings can cause false overspeed trips; only qualified personnel should adjust these.
• Test run: After checks, reconnect battery, clear the alarm, and start the unit while monitoring frequency and voltage. If overspeed persists, shut down and contact a technician.