Five top causes of engine failure and how to prevent them

Jake Kavanagh talks to Sea Start marine engineer Nick Eales about how to avoid the five major causes of an engine breakdown at sea

- Jake Kavanagh

A modern marine diesel engine won't let you down you'll let it down. These words from a time-served marine engineer tend to get to the root of the most common breakdowns, especially when underway - little preventative maintenance, poor quality fuel, or the absence of spares (or knowledge) to help fix the problem in situ.

With a few notable exceptions, such as Bukh and Yanmar, marine diesel engines are almost entirely based on commercial or automotive blocks that have been marinised. This introduces some extra complexity, usually by using seawater as a coolant and fuel that can sit for long periods in the tank between outings.

The environment the engine lives in is also working against it. Salty air, lack of use and changes in temperature can age your engine prematurely. 'Standing' faults from dormancy can also be an issue. Research has shown that an average offshore motorboat engine only runs for around 50 hours a year, with a sailing yacht's engine clocking even less. A truck engine would do that in a fortnight.

However, while automotive engines are packed tightly under a bonnet and have more electronics than Apollo 9, boat engines are usually easier to access and fix. The marinisation process is also very robust, with the service items often sensibly placed. Twin engine installations are sometimes 'handed' so dipsticks and filters can all be reached from the central walkway.

To get an idea of the most common breakdowns, who better to ask than Sea Start, the marine equivalent of the AA; it even uses a similar colour scheme. CEO Nick Eales has been running a fleet of mobile marine mechanics along the South Coast of the UK since 1994, so has pretty much seen it all. In descending order of occurrence, here are the five main reasons the engine will fail, with Sea Start's tips on how to stack the odds back in your favour.

1 Fuel starvation