4.3GL gas in oil

[bunker108]

Well like the title says my oil smells like gas. Oil and filter were changed at the start of last season. It is running fine. I am going to pull the plugs next and then start tearing into it. I am suspecting an intake gasket as I have no idea where else fuel could get into the crankcase.

Is this a common problem?

Has anyone else tacked this and to what degree of success?

Thanks in advance!

 

[Maclin]

Really need to know the engine model and year. Most 4.3's had electric fuel pumps, so most likely it is not that. Mechanical fuel pumps can leak into the block. Most likely the carb is leaking into the intake manifold. If it is a Holley carb then the power valve is suspect. But if it is the carb then you should have some driveability issues with flooding, like hard starting and rough idle and dying at slow idle.

 

[bunker108]

It is a 1998 Vortec 4.3GL with an electric pump and the 2 barrel Holley.

Power valve huh...

 

[bunker108]

I wouldn't say it is hard to start but it does take a few tries and a bit of throttle which I have noticed is taking a little more effort lately. She always starts though. It will die after idling around for awhile.

 

[bunker108]

So the oil is drained and filter is off. What a mess!!!

How do I diagnose the the power valve or is it just a part I replace? It looks easy enough to get to but I will have to pull the carb to get to it.

 

[nitwhit]

Experienced the same issue with gas in the oil last year with my 2 barrel Holley. Carb rebuilt and all is well. Starts much easier too.

 

[bunker108]

That makes sense. I pulled the spark plugs this morning and there is an obvious rich condition. The worst plug was the port rear cylinder. I am crossing my fingers that this isn't as catastrophic as I at first thought.

 

[bunker108]

Nitwhit when you had the carb rebuilt did they find the actual problem? Was it a float problem? Reason I ask is I am still curious about the power valve failure mentioned above.

 

[nitwhit]

They did say the power valve was leaking. When I pulled the carburetor, the intake was very wet with fuel even though I had not ran the engine for a couple of days so it was obvious the carb was leaking. I have the same 98 4.3GL as you and the carb had never been touched so I just had it completely redone by a local carb shop. Was going to attempt it myself but Holley could not cross the OMC/Volvo carb #'s to the correct kit as it an OEM part #. It made a huge improvement to throttle response and starting. Both hot and cold. Be sure and change the oil a couple of times until the gas is flushed out before putting a load on the engine.

 

[bunker108]

I pulled the carb and the intake was super wet. I dropped it off at a local shop to have it gone through. I should have it back tomorrow.

 

[nitwhit]

Sounds like you found the problem. Having a vacuum gauge for final adjustments would be a good idea but they should be able to get it pretty close. I assume you have already changed the contaminated oil. Run it at idle for 10-15 minutes on muffs and then do another oil change. Hopefully you'll be good to go after that.

 

[bunker108]

Nitwhit you were right on the money. The carb needed to be rebuilt. All is well as of now. The real test will be Powell Friday.

 

[nitwhit]

Thanks for the update. Since it was that bad you should notice a significant improvement now. I'm trying to get mine buttoned up and ready for the holiday weekend too.