Question 1

How often should a marine generator be serviced?

Accepted Answer

Oil and filter changes every 250 hours or annually, whichever comes first. Impeller replacement annually regardless of hours. Coolant flush every 2 years. Injector service at 2,000-4,000 hours. Load bank testing annually to prevent wet-stacking (especially if the generator runs at low loads). Belt inspection every 500 hours. Most generator failures are caused by deferred maintenance — the service intervals are short because generators run at constant RPM under load, which is harder on the engine than variable-speed operation.

Question 2

How much does marine generator service cost?

Accepted Answer

Routine service (oil, filters, impeller, belts) on a common yacht generator (Onan, Northern Lights, Kohler) runs $400-$800 per service. A full rebuild on a 15-20kW generator costs $3,000-$8,000. Generator replacement (unit only) ranges from $15,000-$50,000 depending on output and brand. Installation labor adds $3,000-$8,000. Hourly labor for generator technicians runs $95-$160. If your generator is approaching 10,000 hours, budget for a rebuild or start pricing replacements.

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