Marine Generator Sets in Australia

A generator is a second diesel engine on your boat, with its own raw water circuit, its own impeller, its own anodes and its own service schedule — and it is the most reliably neglected machine aboard.

The common names

Onan, Northern Lights, Fischer Panda and Kohler are the sets most often encountered in the Australian fleet, across everything from cruising yachts to large motor yachts.

Why they get neglected

The generator does not move the boat, so nothing about a bad day forces you to think about it. Then on a hot night with guests aboard and the air conditioning running, it stops.

On a boat with full accommodation, the generator frequently accumulates more hours than either main engine, and it does so at a steady load in a hot, enclosed space.

What it needs

• Its own oil and filter schedule, not the main engine’s
• Its own impeller — a separate raw water pump with a separate interval
• Its own anodes, including any in its heat exchanger
• Its own raw water strainer, often a separate one
• Load. A generator run continuously at very light load wet-stacks, building unburnt fuel and carbon. Manufacturers specify a minimum useful load for a reason.

What comes up in workshops

Impellers past interval; heat exchangers never cleaned; anodes never replaced; wet stacking from prolonged light-load running; and exhaust systems corroding exactly as a main engine’s does.

Ask explicitly whether the generator is included in a service quote. It usually is not — see how to get a quote you can compare.

Frequently asked questions

Is the generator included in an engine service? Usually not. It is a separate engine with a separate schedule. Ask explicitly.

Why does my generator have more hours than the main engine? On a boat with air conditioning and accommodation it runs at anchor and alongside, often far more than the mains.

What is wet stacking? Unburnt fuel and carbon accumulating from prolonged running at very light load. Generators need a minimum useful load.

Does the generator have its own impeller? Yes, and its own raw water pump, strainer and anodes.

What fails most on marine generators? Raw water circuits — impellers, heat exchangers and anodes — followed by exhaust corrosion.