Generator controller displays E05 and the engine shuts down abruptly during operation.

Safety: Do not attempt to restart repeatedly. Overspeed can cause catastrophic engine damage. Turn OFF the generator, isolate battery, and lock out automatic start.

• Inspect speed sensor: Locate the magnetic pickup or speed sensor near the flywheel or timing gear. Check for loose mounting, metal debris on the sensor tip, or damaged cable. Clean the tip and ensure correct air gap as per engine manual.
• Check wiring to controller: Trace the speed sensor cable to the Himoinsa controller. Inspect for chafing, cuts, or loose terminals. Repair or replace damaged sections.
• Review governor parameters: Access the controller configuration (password may be required). Verify rated speed and overspeed thresholds match the engine plate (typically 1500 or 1800 rpm). Do not change parameters unless you have the correct Himoinsa settings.
• Inspect fuel actuator (if electronic): On engines with an electronic actuator, check the linkage for free movement and no binding. A sticking actuator can cause uncontrolled speed changes.
• Test run carefully: After corrections, perform a manual start with no load and monitor speed on the controller. If overspeed recurs, stop immediately and contact a qualified technician to inspect the governor and actuator system.