Fuel in oil

[archiethe3rd]

I'm experiencing fuel in my oil on my 78. After sitting most of the winter, I started it a couple weeks ago. It was hard starting, but then went to idle around 2000 rpm and was putting out a lot of white exhaust. I shut it off and noticed a good amount of fluid leaking from the air cleaner housing. I removed the top and cleaned out the residual fluid. It smelled like gas. Later, with the air cleaner top off I tried starting it again. It fired up, went to fast idle then died and shot a spray of fuel out of the carb. It ran for 10 sec. or less. Today I pulled the dipstick, wiped the dirty oil off and smelled the oil. It smelled like gas. I decided to change the oil. When I drained it I got 5 qts of oil and gas mixture out of it. I replaced the mechanical fuel pump 2 years ago. Is there a bad gasket that is allowing fuel in to the crankcase? Any help is much appreciated.

[So Cal Mark]

a gasket won't cause that trouble. Either the fuel pump diaphragm is leaking or the carb is flooding and pouring fuel into the cylinders.

[chrisg]

Ethanol laced fuel and mechanical fuel pumps don't get along well..:especially when left alone together for a while

[archiethe3rd]

Thanks Mark and Chris. Initially when my oil smelled like gas, I freaked (in my head). Couldn't figure out how gas would be in my oil, usually worried about frothy oil. I think it's new fuel pump time.

[So Cal Mark]

the danger is that the fuel will displace oil on the bearings and camshaft

[chrisg]

I had two blow on me in the last year or so. Ultimately, I prefer electric FPs anyway, so it was probably the universe's way of hitting me upside the head for being lazy not going and changing them...but, indeed, gone unchecked you could do some real damage & I gather rather quickly. One of mine showed no running problems, but was leaking into the crankcase. The other was kind enough to make a mess outside the car thus announcing the failure clearly. had it happen on other types of cars in the past but usually associated with obvious fuel pump problems.

[archiethe3rd]

I replaced what I believe was the original mechanical pump. The new one looked about the same but I found out, through help in this forum, that the in and out were opposite the original and how to check that. Are the new mechanical pumps junk? You can find them for $28. I never used any fuel that stated it had ethanol and only put in premium.

[chrisg]

I'm envious of wherever you live. 100% gasoline is available but not terribly common here in TN.