Generator starts and runs but frequency and voltage fluctuate noticeably, causing lights to flicker.

Safety: Avoid touching moving parts while running. Use insulated tools and follow electrical safety procedures.

• Check fuel quality: Ensure diesel is clean and free from water. Drain water separators and replace filters if contaminated.
• Inspect governor linkage: With engine off, ensure all linkages move freely and return to neutral without sticking.
• AVR connections: Tighten all AVR and sensing connections in the alternator terminal box.
• Parameter tuning: Adjust governor and AVR stability/gain settings slightly according to Himoinsa or engine manufacturer guidelines to reduce hunting.
• Professional calibration: Persistent instability should be addressed by a technician with proper test equipment.