Cruising Sailors Forum Archive

Diesel engines

I have not read the link but I am a mechanic and I do run my diesel pretty hard... Yanmar say hull speed for at least an hour a month when the boat is in service. It also gives a "continuous max hp" rating for the engine for use beyond one hour. In my case the engine is rated for max hp for one hour a day, continuous duty is a lower number that translated to about 2750 rpm's of the max 3000 available. I make the one hour per month easily....
I can not think of any way to hurt a diesel more than not loading it once in awhile! Most sailboat auxiliaries seem to just rust away. The local boat yards change many diesel engines that have no hours on them every year. Beyond the "traumatic incident" failure (gross over heating or running without oil, etc) that happens to a percentage of all engine's replaced, I'd wager that most have just not been run enough or hard enough. Diesels need load to heat up to remove the moisture that happens. With normal weekend use most owners give their boats moisture is the enemy.
I change my oil and filters, I adjust valves, I maintain my cooling system very carefully (The design of the cooling system is weak on our engine, it could be made to overheat when it was brand new), I replace fuel filters regularly and I keep the engine spotless ( I clean the engine with WD-40 regularly). The engine looks like it was installed yesterday! The only failure I have had (beyond the already mentioned cooling system that requires such careful maintenance) has been a plugged exhaust riser. This after 7 years and about 1600 hours of pretty hard use. I tend to run at 2500 to 2700 rpm's of the 3000 available, sometimes higher if I want the speed (think Woods Hole). The engine oil stays clear for a long time, the engine starts and runs perfectly, It uses no oil, it doesn't leak. I'd bet that this engine will last 10,000 hours given this use and maintenance. That is something like 35 years out given current operating habits....
Bruce

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