White smoke from valve cover

[rgodales]

Good morning all,

Yesterday we went out for first time after a small remodel on our 17' open bow. When the motor is just idling there is no issue at all, but while underway there is white smoke coming out of the valve oil plug. The big plug to put oil into the motor.

Motor is a 120 hp older mercruiser. Oil pressure is steady at 40psi, oil is clean and fresh, Temp is steady at 130. Motor runs and feels good on responds just fine.

Should i be worry about that smoke? Why is it smoking?

 

[Bondo]

Ayuh,.... Probably just normal crankcase fumes, 'n condensation,.....

No worries, it should be vented into the flame arrester,..

 

[dannys2004glastron175mx]

are you sure its smoke and not steam

 

[rgodales]

I think is smoke. What about if is steam?

 

[dannys2004glastron175mx]

steam is from condensation . As bondo says no worries

 

[rgodales]

Ok thank you guys for giving me some peace of mind

 

[crazy charlie]

Pull the oil fill cap off and look at the underside of it.any sign of beige residue and it may be a warning sign of some water intrusion.There should be vent tubes coming off the valve cover and feeding this "steam/smoke into the carb to reburn.Charlie

 

[UncleWillie]

It could be smoking for a couple of reasons.

If there is some condensation/water in the oil the hot oil will boil off the water as steam.
Steam will have almost No smell and will evaporate in a few feet.
A 130 deg block is not all that warm, so I am guessing the air tempreature is a lot colder than 75 where you are!
All the water should gone and the steaming will stop in about 30 minutes.
If the head gasket is leaking the oil will look like brown milk and the steaming will get worse as the engine warms up.

If the piston rings are going bad, the hot combustion flames will burn some oil in the crankcase.
The smoke will diffuse slowly but not evaporate, and fill the engine area with smoke and leave a long trail of smoke behind the boat.
Piston rings leak in both directions and will pull oil into the cylinders and the burnt oil would also appear as smoke in the exhaust.
The smell of burnt oil would be noticeable in the smoke.
You would likely have mentioned this, so this is probably not the problem.