M-12 Question

[MomentSurf]

I have noticed after long periods of motoring, my engine copmpartment being a bit smokey.  I motored the boat yesterday and investigated...expecting an exhuast leak.  Definitaly not an exahust leak.  I found some smoke coming out of this tube attched to the top of the valve cover. Any idea of what the cause/solution might be?

[Craig]

Sounds like blow-by fumes. Worn rings allow combustion gases to blow by and into the crankcase The tube draws the fumes(positive crankcase ventilation) from the valve cover and into the intake system. How old is your engine? If the tube is leaking it may just need to be replaced or you may need a new PCV valve. All engines have some degree of blow-by which increases with age. In the old days a can of STP was the temporary solution  to worn rings in gasoline engines. Probably NOT a good idea for a diesel.

[BobK]

That tube should lead to the front of the air intake for the engine.  There is some blow by while running your engine - and that should be directed to the front of the air intake where it is run through the engine and out the exhaust.
BobK

[MomentSurf]

That tube should lead to the front of the air intake for the engine.  There is some blow by while running your engine - and that should be directed to the front of the air intake where it is run through the engine and out the exhaust.
BobK

Thanks!  The tube just leads to the shaft area...NOT to the air-intake, thats why my engine room was filling with fumes. 

The engine is original...1986.  Doesn't consume/burn any oil. 

Can some post a pic of how their crank case vent tube is connected to the air-intake.

Where is the PCV valve loacted? I might as well change it....

[Craig]

Your engine may not have a pcv valve. Need to check manual.

[deisher6]

Hey Momentsurf:
I am in in Indiana right now or I would send you a better flick.  This flick is so close....the red tube goes around and goes through a wire loop on the intake, which on Windrunner looks sort of like a hair dryer.  A zip tie would probably hold it in place also.  Both the intake and the open end of the tube point towards the bow.
Hope this helps
regards charlie