Gas in my oil

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Jun 16, 2003
Hull, Mass
In the past year or so I have tried to use a mechanical pump, an electrical and a used mechanical pump.

Right now Im running an electric fuel pump that puts out 4 to 5 psi.

The fuel line I am using comes from the threaded fitting on the side of my tank.

I am not using any return lines.

Im using a Holley 350cfm carb. (Whatever, I dont have linkages to run my rebilt FJ60 carb on my 40, so it sits on the shelf in a plastic bag.)

The electric pump is keyed to the ignition or the acc switch if there is one.

So, did I end up pumping gas into the engine through the carb while I was listenting to the radio while wrenching? Is the pump putting out too much pressure?

I just drained the oil due to a leak, probably caused by the oil which had a viscosity of water almost. I was going to drop the pan and add more RTV since I have a 4 piece oil pan gasket. Apparantly, it was due to the lack of viscous oil. This may have solved one mystery, but created a new one.

Im thinking that just installing a hidden switch to the pump will solve the issue. In the meantime Im looking to get a price on a new mechanical one.
You don't want your electric fuel pump running while the engine is not. You should fix that.
Did the oil smell like gas? Was it overfull?
Dude, it was pretty surprising to see that much stuff coming from the pan. The engine was cold and the oil/gas came shooting out as if there were a pump pushing it. Its pretty much the consistency of kerosene/diesel at this point but the color of used oil.

I actually laughed when it came out. I wouldnt have been more surprised if it were Kool Aid dthat was draining from the pan.
a: Is there a charcoal cannister on the truck any more?

b: Is the tank vented any more??

c: You did bypass the mechanical fuel pump right??

BTW, a strong fuel pump can overcome the float needle and fill the carb up with gasoline..
I dont have the cannister hooked up. The tank isnt vented but I havent had any pressure problems, no whooshing sound or anything. I removed the mechanical pump and blocked it off a long time ago.

I have been planning to install the cannister and whatnot, but have put about 50 miles on it in the two and a half years I've been working on it. When I pull the pan I will be checking for fuel leaking past the carb. I think that was the problem anyways, but wanted a second opinion for a change. If I didnt ask it would be an excuse for me to tear everything apart and start over. ADD and a little OCD mixed in. Wrenching on my 40 has become my meditation. Now that its pretty much done I'll be driving it. Its going to be a weird adjustment not turning wrenches.
With an electric pump the only way to put to put gas in your oil is to over power the needle and seat, fill up the carb, and overflow into the intake and down into your crank case. You may want to rebuild at least the needle and seat and double check your floats (adjustment and condition). Sometimes your floats will fail due to age (get little tiny holes)...take on fuel and well do what is written above. End result is fuel in the crank case.
You might try a fuel pressure regulator in addition to all the above advice. 4-5 psi sounds a little hefty, even for your carb.


Really? Im pretty sure I read on the Holley site that the carb ran at that pressure. Thats why I bought that specific one. I wish I could get some linkages and run the Aisin I rebuilt 6 years ago. Id rather run stock to be honest. The Holley came with one of the cruisers I bought and I never kept the linkages from the stock stuff. I dont know what I need though as far as they go. Im 9/10ths of the way to have it on the road and have just a few small details to take care of.
quick note:- depending on how long you ran ur cruiser and how much fuel was in with the oil it might be an idea to throw a set of main and conrod bearings at it........fuel, oil, and bearings dont play well together
Yeah I know. I blew a 2F in one of my old 60s. I used the kerosene motor flush before moving to MA. I drained it out and put in oil, but never even thought to put in some cheap heavy weight oil to flush out the kerosene from inside the engine. The good thing is that I drove it with a bad ring in #4 from VA to MA, and then to my new job for a month or so (@ 8mpg) before it completely gave up. It gave me a whole new respect for inline 6 engines.
When I pull the pan today Im going to toss in a magnet to see if any shavings came out. Im going to do a compression check as well. Then I am going to put in some 20W40 or something to run through there to pick up any gas still where it shouldnt be. Then go back to regular 10W30.

If its bad, Im going to use it as an excuse to put in a 3fiddy once this one blows.
give each cylinder a squirt of oil before you start it again. Gas is very good at cleaning cylinders. Locking a motor up sucks..
....and when I gave my piggie a gas douche...after putting a new fuel pump in and draining out all the gas/oil and fitting a new filter and some 20W50 for starters....I was billowing blue gray smoke like a skeeter fogger (not that bad but bad enough). Gave myself a scare, but the vacuum gauge pointed to oil getting past the guides (or in this case the valve stem seals). I suppose the gas/oil mixture was not kind to some aged valve stem seals and was the last thing that put them in their grave. Put new valve stem seals in and viola, no more bug fogger.

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