I have a 37 efi on a mudbuddy it's getting fuel in the oil it's been at the Briggs shop for over a month. They caint find the problem. It has had cam, heads, muffler and air filter put on it. Briggs says it's because it has performance parts on it that causeing the problem . I don't buy that. The guy that done the work has lost of motors out there that he has built with no issues. Not trying to get them to warranty nothing just want to figure out why it's getting fuel in the oil. Any help is appreciated

Tell your Briggs guy after you have it back in your possession that these engines are capable of over 240 compression without fuel in the oil. Check the rings, check your head gaskets. If he thinks the work is the problem, he doesnt need to be working on it.

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Where are you located? There are quite a few scattered around that would help you figure it out for a free beer or 2. Marcus or Will C would not only figure it out, but they'd fix it for you and they know what they're doing. They arent gonna charge you any more than your Briggs guy, either.

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#GhostBoat
#Whoneedsphysicsihaveamudmotor

I'm in lower Arkansas

South Arkansas

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#GhostBoat
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If motor passed a health check it could be as easy as putting a shutoff valve in the fuel line. The tanks get hot and will shove fuel into the engine while they are sitting. If I can be of help just holler

Have you contacted the guy that built it?

I've seen the float in the fuel pump module leak fuel from the vent to the throttle body causing an over rich condition before. Its a possibility. To check you pull the vent hose from the TB and put a bottle on it. Plug the TB hole and go for a ride. Fuel in bottle = fuel getting in motor.

It was the float in the fuel pump module thanks

How did you determine that was the problem? I'm pretty sure mine is doing the same thing.

How does an over rich condition put gas into the oil? Doesn't that just mean more gas will go into the carb?

I guess I'm asking for me now. How does fuel get into the oil on a carb motor? And it didn't happen while in storage because I changed the oil immediately before my last bowfishing trip and the oil level was higher by the end of the trip.

Pressure in the tank over powering the float or a stuck float are two most likely things.

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The new tank vents don't work till ya take the guts out of them and drill them out. My tank swelled up like a toad.

Still though, how does the fuel get into the oil coming from the carb? What path does it take?

^^^^ what he said!

Can it do that when it's running or does it have to be sitting up to do it? What about if it's firing on one cylinder?

Most common while it's sitting, or idling if it's pouring more gas in than it can burn and yes can do it firing on one cylinder. You're not burning the fuel and it's gotta go somewhere.

One more quick question about diagnosing the fuel pump. If the fuel pump is stuck open, how does the gas get into the breather? Does it pump more gas into the carb, then into the cylinder, then doesn't burn it all and then somehow gets into the head cover?

Bueller? Bueller???