Generator starts and runs but the building experiences lights flickering and unstable voltage during load changes.

Safety first: Monitor voltage and frequency with appropriate meters and PPE. Avoid connecting sensitive electronics until stability is restored.

• Check connections: Tighten all alternator output and sensing connections, including small gauge wires to the AVR and controller.
• Measure frequency: Use a frequency meter to ensure engine speed remains stable around 60 Hz (or 50 Hz). If frequency is unstable, address governor or fuel issues first.
• AVR adjustment: If the AVR has adjustment pots, fine-tune voltage and stability according to Kubota service instructions. Small adjustments only.
• Replace AVR: If voltage swings remain large despite good connections and stable frequency, replace the AVR with the correct Kubota part.
• Load management: Avoid sudden large load steps; stagger starting of big motors where possible.