Engine maintenance: How to keep your boat’s heart in good shape

Ahoy, mate! Captain D here. Let’s talk about a vital aspect of owning a boat: Diesel engine maintenance.

Diesel engine failures are one of the main reasons for lifeboat call outs. But luckily for you, many malfunctions and breakdowns can be easily fixed or avoided with just a little know-how and some tools, so let’s review some of the ways you can achieve this, shall we?

  1. Perform some regular maintenance on the engine: This one is fairly obvious, mate. A self-respecting boat owner is aware of the need for routine servicing, so by no means skimp this aspect of maintenance.
  2. Be always on the lookout for troubles: When you’re actively looking for issues or malfunctions on your engine you stand a pretty good chance of spotting them before they turn into a real problem. Let’s say you do this and discover a build up of black dust around the alternator or water pump belts. This would indicate accelerated belt wear, usually for lack of tension, or badly aligned pulleys. Knowing this, you’re in a better position to act.
  3. Listen to your engine: The sounds your engine make can help you identify problems. For instance, the note of the engine and its exhaust can tell you much about the engine’s condition. When you start it, it does more or less instantly on all cylinders or is it more of a slow thump before they all fire up? If so, there’s an issue that must be addressed pronto.
  4. Check the voltage: This is an easy way to test the condition of the engine start battery and its connections. All you have to do is connecting a digital voltmeter across the battery terminals while tuning the engine on the starter motor. Since the starter motor draws a large current, the voltage will fall well below 12V but should be greater than 9.5V and ideally around 10V while cranking. Checking the cranking voltage a couple of times a season can help to identify a battery that’s nearing the end of its life.
  5. Take a fuel sample: Clean fuel is capital for the good functioning of diesel engines. Any water in the tank can cause the growth of bacteria that can block fuel filters. It’s your job to check there is no water in your tank. Since water is denser than diesel, it collects at the bottom of the tank and most tanks have an inspection hatch of some kind that allows a hand pump to be inserted into the top of the tank. Use a plastic bottle to check the fuel comes out clean.

There you go, mate. With these simple tips, you ought to be more prepared to deal with malfunctions on your engine and even in a position to prevent them. This will help you prolong the lifespan of your engine and your boat.

Better safe than sorry, Skipper.


See you on the waves, 

Captain D.