Oil on throttle valve

[akmoosehauler]

I have oil in the intake box and on the butterfly valve.
Cleaned the box out the best i could and wiped out the throttle body/valve.
What could be going on with this.
Motor is an 07 DF140 with just 115hrs.

This is in addition to the other troubles i have with the motor.

Thanks

 

[rodbolt]

Re: Oil on throttle valve

do a leak down test.
if the test is good the oil is normal blowby condensate.

 

[jp10]

Re: Oil on throttle valve

Just getting my feet wet here, could it possibly be from the engine oil tank, the smaller one? I know on the HPDI oil will seep from the cap when the motor is horizontal. I found the zip tie solution on this board and seems to be holding.

Rodbolt, could you please take a look at my "Myth Busters" thread and give your expert opinion please.

 

[akmoosehauler]

Re: Oil on throttle valve

do a leak down test.
if the test is good the oil is normal blowby condensate.

Thansk Rodbolt.

Valve and surounding are were darn near completly black.

 

[rodbolt]

Re: Oil on throttle valve

marine 4 stroke engine venting is about 1960's technology right now.
its about 1 step up from a down draft tube.
all 4 stroke engines have to vent, and if combustion gas blowby is excessive it vents a lot.
this vented gas is a mixture of oil vapor,water vapor,air and fuel.
its routed from the crankcase,typically a cam cover,to the airbox where intake vacum will draw it in and burn it.
sometimes this vapor will condense and create some standing oil in the airbox and throttle assy.
you dodnt see it on cars due to better venting technology and most car shutters dont spend much time horizontal.
so do the leakdown to test cyl sealing ability,if its ok go enjoy.