Today’s marine diesel engines are much more reliable than older models. While older diesel, gas and outboard engines used to break all the time, their modern counterparts are made to be much more durable. If you make sure to provide the engine with routine maintenance according to the manufacturer’s specifications, prevent them from overheating, use clean fuel, and don’t push them too hard, you can rest assured that the engine will serve you loyally for years to come.

That said, even the most sophisticated, well-kept engine is prone to malfunctioning. Once you’ve experienced such a problem, there are three ways you can resolve it: repair, rebuild, refurbish or replace. In this article, we’ll explain what each of these entails and which one is the best for your engine.


You probably understand what repair means. It involves replacing the key components of the engine that may be causing the malfunction, anything from the water pump, starter or the alternator. It also means fixing a leak from an oil valve or replacing a corroded part. All the easy stuff that’s not that far from maintenance. Repairs can be very expensive, but a reputable ship repair company can make sure all the loose screws are tightened. This usually means that the repairs are well worth both the effort and the money, and can be much cheaper than the other two alternatives.


Rebuilding the engine is done when the issue inside the engine is more serious. It involves removing the engine from the boat, taking it apart completely and dealing with the issue, cleaning the rest of the engine and finally putting it back together using brand new parts issued by the manufacturer. Sometimes the engine can be rebuilt without having to remove it, but this is usually reserved for small repairs like cylinder head replacement. Rebuilding is done in a professional ship repair facility by skilled and licensed mechanics. After they’ve completed the repairs, the engine goes back into your boat as good as new.


Refurbishing is the next best thing to replacing your engine completely. The process is done in a factory where the engines are completely taken apart, cleaned, inspected and put back together following the manufacturer's specifications and using a lot of brand new parts. If you choose to buy a refurbished engine, you will not get all of the components like intake or exhaust manifolds, fuel supply system, alternator, starter, etc. Instead, they have to be bought separately or you can use the existing ones on your boat.


Of course, there’s also the option to replace your existing engine with a brand new one if the damage is too extensive. In most cases, this tends to be the most expensive option but one that pays off most in the long run. You can make the decision after you’ve had an expert technician look at the problem and give you an estimate on rebuilding. If repairs are not an option, it boils down to a refurbished engine or a brand new one.

Which One to Choose?

There are a few catches with buying refurbished engines, other than the ones we already covered. First, there’s the issue of warranty. Such an engine is usually covered for 18 months to two years. Then, there’s the issue of having to hire a mechanic to perform the installation. Besides, companies only sell these engines to licensed ship repair companies precisely because of the installation process. A lot of reputable companies like Cummins offer refurbished engines build according to their own specs and even offer various incentives, as you can learn here:
Finally, the choice is up to you. If your engine can be repaired or rebuilt, just make sure to choose a reliable, experienced technician to make sure the problems don’t come back once you’ve covered the tab. If the choice boils down to buying a refurbished engine or a brand new one, figure out which option is better for your wallet now and in the long run.

Contact Propulsion Controls Engineering at

1620 Rigel St, San Diego, CA 92113, USA