1993 PCM 351 Gas leaking into Crank Case

Any idea's on what can cause this problem? I've checked the floats in both carb bowls and they seem to be working fine. I've read that the marine fuel pump is designed to prevent this from happening if it fails but I havent gotten that far yet. Any help or suggestions will be greatly appreciated. Thanks!

Yes, the oil smells like gas. I did have a leak on the fuel line where the line enters the carb but when I shut the engine down, it stopped leaking. Also for the brief time I ran the engine, the engine was blowing greyish white smoke out of the exhaust similar to the smoke I've seen previously from a burnt water pump impeller.

I've taken the carb off and checked the needle and seat. It looks good too. I even had a mechanic friend of mine who is pretty much an expert on Holley carbs to check behind me and he found everything to be fine also. He seems to think it's fuel pump related but I haven't had a chance to check it yet.

Your statement about the fuel pump on a marine engine being designed not to do that is incorrect. If the diaphram on the pump goes it will leak fuel into the clear transfer tube attached to the air cleaner and into the carb.

Your leak going to the carb is a serious safety hazard even if it stops when the engine isnt running. Try not to die! fix it asap.

The most likely cause is indeed dripping from the primary or secondaries which you should be able to see by looking down the throat of the carb while the motor is not running. Lately needle and seat valves have been proving faulty quite often. I have seen a bunch of them, new and used and I have had ones that look just fine to me- leak like a sun of a gun.

If you see one dripping... replace the corresponding needle and seat.

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