Generator emits heavy black smoke under load and seems to struggle to maintain speed, but no fault code is triggered.

Safety first: Ensure adequate ventilation around the exhaust outlet. Black smoke indicates soot and incomplete combustion.

• Check load: Reduce the connected load and observe whether smoke decreases. Keep load within Kubota's rated kW and kVA limits.
• Inspect air filter: Remove and inspect the air filter. Replace if dirty or oil-soaked.
• Exhaust restriction: Inspect the muffler and exhaust piping for dents, internal collapse, or foreign objects. Replace damaged sections.
• Fuel system: If smoke persists at moderate load, have the injection pump and injectors checked for overfueling or incorrect calibration.