FT 9.9 getting fuel in oil crankcase

[Deepwatertroller]

I have an 86 9.9 fourstroke kicker motor that is getting raw fuel in oil crank case. I had O-rings in fuel pump replaced, carb rebuilt, and bimetal valve replaced. If I pull plug out of bottom cylinder it looks like it's receiving a richer fuel mixture. The motor starts fine and doesn't smoke. Would oil seperator have anything to do with this? I'd like to get this problem taken care of before I put the boat in the water. Any help would be greatly appreciated. Happy New Year!!!

[boats.net]

Most of the time it's the carb. Did you replaced float valve in carb? Also check gas tank if not venting properly it can over pressurize and flood carb., look at vent on gas cap.

[Deepwatertroller]

Boats.net thanks for the reply. I'm pretty sure that float was included in Yamaha rebuild kit I purchased. It was rebuilt by professional carb shop. The motor is fed with it's own fuel line off main tank (120 gallon) so it should have enough pressure relief. I do notice that after having kicker running for several hours that motor may sputter and I have to pump up primer bulb and it runs fine. 6'fuel line and primer bulb have been replaced along with fuel/motor connector.I have also made adjustments to lean/rich mixture screw.Any other suggestions?

getting raw fuel is only 2 things
fuel pump seals, singe it uses crank case pressure to pump
maybe the intake valve seals also

[Deepwatertroller]

Is there any way of testing valve stem seals? will cylinder compression tell me anything?

I found my receipt for Yamaha Carb rebuild kit # 6G8-W0093-00-00 does that include float?

yes that included float

u need to do a leak down test

[Deepwatertroller]

Thank you for the reply Just-In-Time. What is a leak down test? What is involved in performing one?

leak down test
u close the intake and exhaust valve per cylinder, by rotating the cam to close them, then u pressurize the cylinder
if u here are coming out the exhaust mani u need a valve job or seals, same as for intake, u will here air coming out the intake

[Deepwatertroller]

Thank you Just-IN-Time. I will try this over the weekend.