Your Old Diesel Motor: Replace or Rebuild?

By Practical Boat Owner

At what point is keeping an old boat engine throwing good money after bad? PBO expert Stu Davies has some tips to help you decide…

Most of us will know someone – and may have been that someone ourselves – with a rusty, rattly, oily or smoking marine diesel engine. The sort of old boat engine that no longer fills us with complete confidence in its reliability.

Many have also been in the position of thinking of buying a second-hand boat with concerns that the engine may be suspect or isn’t performing quite as it should.

First questions when assessing an old boat engine

The first thing to do is set a baseline so any decisions or spending of money are based on cold, hard facts. This entails putting the wallet firmly to one side and rapidly getting an answer to the frank question: ‘is my engine actually shot?’

If that’s the conclusion, the immediate follow-up question is always ‘do I need to buy a new engine or can I refurbish what I currently have?’