Controller displays “Overspeed” and shuts down the generator shortly after start; engine sounds unusually fast before shutdown.

Safety first: Turn generator OFF and disable automatic start. Do not attempt to run an engine that is overspeeding, as it can cause severe damage.

Steps:

• Inspect throttle and governor linkage: With the engine off, move the throttle and governor arms by hand. They should move smoothly and return by spring tension. Lubricate pivot points lightly if sticking.
• Check speed sensor: Locate the magnetic pickup or speed sensor near the flywheel or ring gear. Inspect the connector and wiring for damage. Ensure the sensor is mounted at the correct gap per Eaton/engine specs.
• Controller settings: Verify in the Eaton controller that the engine speed and frequency settings (e.g., 60 Hz) are correct for your region and model.
• Test governor actuator: On electronically governed units, observe the actuator during a brief start attempt (if safe). If it drives the throttle fully open uncontrollably, the actuator or controller output may be faulty and should be replaced by a technician.