Generator attempts to start but stops with E03 displayed, engine speed surges briefly before shutdown.

Safety first: Disable automatic start, disconnect battery negative, and keep hands clear of rotating parts.

• Inspect speed sensor: Locate the magnetic pickup sensor near the flywheel ring gear. Check for metal debris on the sensor tip and clean it with a lint-free cloth. Ensure the air gap to the ring gear matches Kubota specifications (typically 0.5–1.0 mm). Adjust if needed.
• Check wiring: Follow the speed sensor harness back to the Kubota controller. Look for cuts, abrasions, or loose connectors. Repair or replace damaged wiring.
• Inspect flywheel teeth: Rotate the engine by hand (using the crankshaft pulley bolt) and visually inspect ring gear teeth through the sensor opening. If many teeth are damaged or missing, the flywheel may need replacement (technician recommended).
• Governor actuator check: Observe the electronic governor actuator linkage at the fuel injection pump. Ensure linkage moves smoothly and is not binding. Lubricate pivot points lightly and verify return springs are intact.
• Controller settings: In the Kubota controller menu (if accessible), verify rated speed (e.g., 1800 RPM for 60 Hz) is correctly configured. Do not change advanced parameters unless you have the service manual.
• Test run: Reconnect battery, clear E03, and start the generator while monitoring frequency and voltage. If overspeed persists, contact a qualified technician.