smoking yanmars at 2000rpm

[malc60]

I have a rodman38 with two 370yanmars, beautiful engines, only 430 hours, at 2000rpm they smoke, below and above this they,r ok, underneath as been cleaned, it seems only when lifting on the plane or going thro the turbo boost,, when i come down thro 2000 they seem ok,is this normal? hope so.

 

[rafiki_]

I'm sorry, I don't know anything about these particular engines, but wondering if your air filters need cleaning/changing?

 

[omega2]

This sounds like the onset of blocked inter-coolers, my mates one got to the the stage were it would not rev above 1500, and loads of black smoke. We found the inter-coolers blocked solid with muck. The solution was to get them off and then remove the matrix and then power wash. The cause was the breather pipe from the rocker cover "feeding" the turbo, via the air cleaner. Bad set up, reroute the pipe after you have cleaned.

 

[Latestarter1]

This sounds like the onset of blocked inter-coolers, my mates one got to the the stage were it would not rev above 1500, and loads of black smoke. We found the inter-coolers blocked solid with muck. The solution was to get them off and then remove the matrix and then power wash. The cause was the breather pipe from the rocker cover "feeding" the turbo, via the air cleaner. Bad set up, reroute the pipe after you have cleaned.

Spot on!

OP does not say if motors are LYA2 or 3, most likely LYA2. If motors are by chance LYA3's as soon a bottom is fouled AFC response is incapable of adjusting to the changed load pattern, however I would go for CAC's as first call.

 

[malc60]

thank you, very helpful.