Gas in oil need help

[Thompson66]

I have a 1966 Buick OMC v6 225 cubic inches engine. I believe that I have gas in my oil. My engine idles fine but it was coughing under load. Among other things, I checked the oil and it was thin with a gas smell. I do not believe that it is water because it is not milky and there is no separation of water from oil. I conducted a side by side comparison test. I drained the oil and got about 5 qts. My engine holds 4 qts of oil. This means that I have an extra qt of something. I pulled my carb and it was clean. All passages were open. I unbolted my fuel pump and checked it with a vacuum gauge. The upper and lower chambers held vacuum without leaking. Where else do I need to check? I am inclined to believe that it’s a bad fuel pump, given that it was running lean under load. But why is there no vaccum lost? If it is in the Carb and loosing that much gas, why would it idle without flooding out? What do you fellas think?

 

[Don S]

Re: Gas in oil need help

Replace the fuel pump with the proper "MARINE" fuel pump.<br />That is what happens with mechanical fuel pumps at times. Quite common.

 

[Thompson66]

Re: Gas in oil need help

Thanks for the quick reply Don. It is a carter marine pump made for this engine. The part no. is 380986

 

[Don S]

Re: Gas in oil need help

Is it the mechanical pump that bolts to the fwd,starboard side of the engine, just above the oil pan?

 

[Thompson66]

Re: Gas in oil need help

That is correct Don.

 

[marinemech1]

Re: Gas in oil need help

make sure engine is running on all six as a non running clyinder could make oil (contaminate) definitly replace pump

 

[Thompson66]

Re: Gas in oil need help

All 6 cylinders checked at around 130 lbs

 

[marinemech1]

Re: Gas in oil need help

are they all running look at plugs to be sure you don't have a wet one

 

[Thompson66]

Re: Gas in oil need help

Yes they are all firing. The plugs look a little cold but nothing weird. I pulled each wire at the cap while it was idling and did notice a miss with each cylinder.

 

[Don S]

Re: Gas in oil need help

Sounds like they are all firing, change the pump.

 

[Thompson66]

Re: Gas in oil need help

Thanks Don, will do and keep you updated.

 

[ScottieinNC]

Re: Gas in oil need help

Please keep us updated if you think you resolved the gas in oil problem. I think I may have the same in a 1996 4.3LX Mercruiser.<br />Thanks,<br />Scott

 

[Bondo]

Re: Gas in oil need help

Scott,....A 1996 4.3l Mercruiser uses an Electric Fuelpump........No Leaks into the base with these........<br /><br /><br />Thompson,......You say it's running Lean......And, you say the plugs Look Cold..??....<br /><br />Just What Color,+ Condition would that Look Like ????

 

[notinbig]

Re: Gas in oil need help

Yer right bondo....... Lean, yet plugs look COLD?

 

[tommays]

Re: Gas in oil need help

black, brown , white ,ect<br /><br />tommays

 

[trog100]

Re: Gas in oil need help

i think u should just replace the fuel pump.. correctly (to the full mark on the dipstick with the engine level) refill your engine with oil and start again from there.. keep a carefull eye on oil level and see if the engine runs better.. <br /><br />trog100