If a diesel engine sits unused over winter, running it periodically can be beneficial—but only if it’s done properly.
Running the engine circulates oil, moves fuel through the system, and, once it reaches full operating temperature, helps remove moisture that can build up in the engine and exhaust.
However, simply starting the engine for a few minutes every couple of weeks can do more harm than good. If the engine doesn’t reach operating temperature, condensation and soot can build up rather than be burnt away. If you choose to run your engine over winter, operate it for around 20–30 minutes and, ideally, take the boat out so the engine is working under a moderate load rather than idling.
If you don’t have time to do this, winter is the perfect time to book an engine service. A qualified marine mechanic can identify any maintenance issues and ensure everything is in good working order, so your boat is ready to hit the water when the warmer weather returns.