Marine mechanics are often asked, “How long are boat engines supposed to last?” That is a very difficult question to answer, given that there are so many variables involved in the size and type of marine engines, particularly among those for motor yachts.

But, the good news is no matter the type of engines your yacht may have, there are steps you can and should be taking to make them last longer. Properly maintained engines could last the life of your boat!

However, before we get to those tips, first, a little “boat engine 101.”

Gasoline Vs Diesel Engines

In general terms, when speaking of engine life, diesel engines tend to outlive gasoline engines. There are basically two reasons why that is the case.

First, diesel engines makes fewer revolutions per minute (RPM) at any given speed than their gasoline driven counterparts. Fewer RPMs means less wear and tear on the engine. The other reason is also related to wear. Diesel fuel contains oil as an additive, which means it provides not only power, but additional lubrication. Gas, is just gas.


Why Do Engines Wear Out?

Without getting into too many details of the mechanics of marine engines, much like your car’s motor, they provide power to a driveshaft via combustion and the turning and cranking of many moving parts. These parts such as, pistons, rods, valves, etc. are subject to a lot of stress and a lot of wear. Also, much like your car’s engine, the best way to minimize that wear and tear is to change your oil at regular intervals.  How often you change your yacht engine’s oil depends on use and other factors, but start with the manufacturer’s recommendations.

Of course make sure whoever changes your boat’s engine oil is a qualified boat mechanic, and knows how to do it right, as well as how to properly dispose of the old oil.

The other way to extend the life of your boat engine is to help her burn fuel more efficiently. The better your engine burns fuel, the less hard it works. The simplest way to increase your fuel efficiency, is to “throttle back,” and as often as possible, run your yacht at a steady and comfortable cruising speed. Again, this tip can similarly extend the life of your car’s engine, but marine engines face something that car engines do not – corrosion.

The sea is hard on metal. Corrosion is probably the leading cause of marine engine failure. Marine engines are constantly at war with corrosion.

Your engines need to be inspected at least once a month for signs of corrosion. If it is found, it needs to be thoroughly removed, right down to the bare metal. Then, the area has to be primed and repainted with your engine-manufacturer’s approved marine paint.

Corrosion to a yacht engine is like cancer, and like cancer, the earlier you detect and aggressively treat it – the longer your engine will live!

outboard motors

Operating a motor yacht can be costly. You can reduce your expenses, and avoid costly repairs by keeping her well maintained. On Demand yachting from FYM can help. If you would like to learn more, or if you have any questions or comments about this blog post, do not hesitate to contact our Yacht Management specialists, or call us at (855) 318-6328.