For the first twenty something hours, my PD was fine. Now at around thirty hours it is getting oil in the fuel. The fuel tank is in the bow, and the boat is equipped with an electric fuel pump mounted on the transom.

I don't know the exact volume, but the gasoline will raise the oil level about 1/8" on the dipstick in approximately one hour of running time.

The fuel tank vent is wide open. The fuel tank is located well below the carb. There has been no change in performance since this began.

Am I looking at a needle valve issue, or something else?

I would not run it until you figure it out the gas will break down your oil fast. Just a thought but your float in the carb maybe stuck.

What psi is your pump? Also, as mentioned, I would not run it until you get it figured out. Gas is a horrible lubricant. You can do a lotta damage real quick.

could your rings be stuck?

the carb could be filling up while the motor is dead and getting into the intake then leakin into the crankcase through the cylinder.

I would put a shut off valve somewhere to stop the flow when the motor is dead.

I'm not sure what psi the pump is rated for. It was installed by the dealer. I was wondering about the stuck float, would that have any other symptoms?

i would go with Stuck Float..

or, if your fuel pump is over a 7PSI.. it could force too much fuel

Check the float. Do you have the stock and electric fuel pumps? If so run it with the stock pump only and see if it still happens. Is the electric pump running continuously? I believe it should stop pumping at max pressure.

its most likley doin it while the motor is dead, it would just boil back out when its runnin. I would clean the carb and go from there, its a mikuni right?

I would think the stuck float would cause the motor to load up, but I'm just guessing. I think leaking rings can let fuel in to the oil also. Don't really know what else could cause it. Try disconecting the e-pump and see what happens. Change your oil before running it, and don't run it too long without checking again. I'd be really careful how much you run that thing until you figure it out.

You say the motor only has 30 hours on it. How old is it? If under warranty, I'd get that thing in to the dealer pronto!

I don't see a stock fuel pump. The line leaves the electric and goes straight to the carb. It is a Mikuni carb. I believe the pump is running continuously, although it is impossible to hear whether it is running or not when the motor is wound up.

If the fuel pump were forcing fuel through the carb, would some of it come out of the overflow tube that comes off of the bottom of the mikuni?

As soon as I noticed it was "making oil," I changed the oil and filter, and have only run it for an hour since.

I've only had the rig since November, however the folks at ProDrive said the the L1 mod voids the Briggs Warranty.

Change the oil. Put a shut off valve in the fuel line, cut it off and let the motor burn all the gas out the carb whenever your ready to kill it. Do that and see if fuel is still gettin in the crankcase, my bet is its floodin in there from the carb while the motor is off.

Where did you get the Mikuni- did it have the float valve replaced for these applications? Thats the first step on a BPS kit install. Also, hook the pump to the ignition so it only comes on when you engage the key PD could probably give you the exact wiring instructions you need (i.e. check the dealer's work).

The mikuni was installed by the dealer. The electric pump is wired through the ignition and produces 1-4 psi.

I spoke with the technician who built the motor today. He believes that if no fuel is coming out of the overflow, and there is no problem with performance, that it is not an overpressure or float/needle valve problem.

However, I have been leaving the engine on full choke for extended periods (3-10 minutes), making sure it is warmed up before use, because we have been hunting in sub freezing temps for weeks. He said that excessive use of the full choke can cause excess fuel to seep past the rings and into the crank case.

I am going to change the oil again, not choke the engine for more than a few minutes on cold starts, and see what happens. I'll have a test run on Wednesday.

When you park it trim the motor down also, we have found that trimming them up can allow gas to flow out of the carb into the engine if any pressure is present.