[QUOTE=Miguelso;2000568]New to this forum, so Hi to Everyone !
We bought our boat about a year ago and it has a Yanmar
4cyl. It runs great, starts in a second every time, even in cold weather
, no knocking nor excessive vibration, but it smokes blue (it can use some paint
too). Most noticeable when cold and less afterwards. The hour meter was broken and stucked in 5k hrs so it probably has way more hours than that, but not much more info about it's history
. I know blue smoke means its burning oil, but after about 30 hrs I didn't notice any change in the oil level. I wouldn't pay much attention to it if I would use it only to get in and out of the dock
or maybe to motor
for 50 hours during the summer. But next year we are planing to go down the ICW
and to the Islands, so I'm debating with myself with "if it's not broken don't fix it" and that I don't want the engine
to ruin our trip. Any thoughts?
The oil control rings could be partially stuck. I really doubt that it is valve guides or valve stem seals
Perform to back to back oil changes, 10 hours apart.
Afterwards get a compression
check. Get a real oil pressure check, at operating temperature.
I would not overhaul
it. Use the money
some other way.
Make sure the RPMs it maxes out to are in the ball park, and keep the fresh and raw water
systems in good condition.
It may have sit around for years without proper oil changes, which will cause rings to stick.
Black smoke is an injector dribbling or not spraying correctly, but blue is oil burning.