Yanmar 4JH3TE 2001 GEAR BOX KBW21 year 2001

[johnmort]

looking for advice on above engine 2001 with 4350 hours runs smooth, starts first time every time but lots of smoke at start up, smoke diminishes as engine warms up but always some smoke ( hard to see when looking back but definitely there) from the exhaust emissions. 21 inch Max prop, engine rpm 3800 ran at 2000rpm while cruising but always last 30 mins at 3000rpm with 15 min cool down. new fuel injectors 2016, turbo clean, air filter clean, exhaust elbow clean 3 inch dia exhaust, oil changed twice a year, engine in a Beneteau First 47.7 sailboat, we bought in 2012 with 3300hrs on the engine, engine smoked as described when we bought the boat. 2021 we will go offshore for 2 to 5 years thinking do I replace engine now or wait till something serious happens? rebuild or new? rebuild to remove smoke I am thinking new piston rings top end. Advise on best course of action?

[rbk]

Have you checked the valve clearances lately? It is time for a top end job but you can probably leave the bottom alone for now. De-carbon the head and lap the valve, check the timing and injectors.

[daletournier]

I resurrected an old thread by Dock head this morning on this exact thing.

It's titled Yanmar problems. I'd attach a link but not quite sure how I do that on my phone app.

[daletournier]

Here you go,

http://www.cruisersforum.com/forums/...d.php?t=122899