Yanmar 4JH 3E Lifespan

[sailorboy1]

Originally Posted by GordMay

Indeed.
The key is to bring the engine up to specified operating temperature.

I agree and have always thought the "load" agurement was false. Just can not see how pushing my engine at 3000 rpm is "better" for it than runing it at 1500 rpm. But I but always allow it to run unloaded a while for warm up before giving under way, run it under load a while afterwards till it fully warmed up to operating temperature even if I need to motorsail a while when I could have gone to just sails, and I always give it a cool down time under no load prior to shutting down to allow the engine temp to equalize. This is how my Yanmar manual says to run it. Nothing in my Yanmar manual says to run it hard all the time.

[GordMay]

I don’t recommend operating at either extremity.
I don’t advise idling to “warm up” an engine (just a few seconds to get lubricated), nor loafing along at 1500 RPM, nor pushing maximum load limits.
Like others, I recommend cruising at the “sweet spot”, often about 80% of continuous RPM rating.