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Yanmar 40 HP 3JH3E engine problems
The Yanmar 3JH3E 40hp in my boat has been a great work horse. Last season I replaced the primary and secondary filters and I have bled the system.
What I am finding now is that after running the engine in gear for 30 minutes or so, it tends to just drop power and then rev up again. Occasionally it does drop power and cut out completely, but most time it just looses revs then up again. I normally run the engine at 2500 revs, but this also happens when running at high revs of around 3500. This weekend the engine ran smoothly for 3 hours (no wind on the east coast of England) and then stopped... but each time it happens it starts quickly and off we go again.
The engine sounds great, no overheating, no smoke of any colour and has plenty of power
Just wondered whether you had any idea, before I get the professionals in the look at it?
Last edited by johnlbailey; 05-27-2014 at 09:06 AM.
Reason: more information