gas in oil

Mar 11, 2008 3 Replies
C

i've got a newly rebuilt engine (old case and pistons, but i think most of the rest of it is new [new rings, push rods, valves, etc.]) and i've changed the oil two times since the rebuild which was about 600 miles and 4 months ago. noticed with this oil change that there was a gas smell in the oil and that the oil didn't look or feel right either. is this a normal symptom of a newly built engine or did something go wrong? also, put on a new carb recently and i can't say that i'm the best at tuning those things so does that have anything to do with it?



-c


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D

carb or fuel pump maybe

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S

Gas smell or exhaust smell? Rebuilding an engine often implies honing the cylinders. This actually makes the cylinders a bit leaky while the engine is being run-in, and exhaust fumes escape from the combustion chamber to the oil sump. This accounts for the oil smelling of exhaust. This will improve with time. Change the oil and see it gets better.

If the smell is uncombusted petrol, the story is different: there is two likely ways for you o get petrol in the oil sump. Faulty gas pump or faulty Carburator. Most likely the float-needle valve and/or seat in the carb is faulty or sticking. There is no reason a new (or rebuilt) carburator could have a manufacturing fault. The float element itself also could be leaking and have "sunk". It is therfore not working as a float anymore, and petrol will leak into the engine through the intake manifold:)

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C

thanks. i'll look at it at my next oil change to see if the new carb is good.

-c

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