E03 displayed and engine shuts down shortly after starting, with fuel present and normal cranking.

Safety: Do not attempt to run an overspeeding generator. Isolate battery and mains/breaker before inspection.

• Verify actual speed: If possible, use a handheld tachometer on the engine flywheel or crank pulley to confirm whether the engine is truly overspeeding or if it is a false signal.
• Inspect speed sensor: Locate the magnetic pickup / speed sensor near the flywheel ring gear on the JCB engine. Check for loose mounting, damaged cable, or metal debris on the sensor tip. Clean and reseat with correct air gap (typically 0.5–1.0 mm; confirm spec).
• Check governor / actuator: Inspect the mechanical or electronic governor linkage for binding. Ensure the fuel rack moves freely and returns to idle when released.
• Wiring checks: Trace the speed sensor harness back to the JCB controller. Look for chafed insulation, oil contamination, or loose connectors. Repair or replace damaged harness sections.
• Reset and test: After corrections, clear the E03 alarm and perform a no‑load start. Monitor speed and frequency; if overspeed persists, have a technician check governor calibration.