# Gas getting in engine oil, 18hp B&S



## ronpaul (Dec 6, 2011)

Trying to get this old 1992 craftsman rider with 18hp I/C back to life.
I rebuilt the carb. as it has been sitting years and maybe I rebuilt it wrong.
I primed the carb and engine ran good for about 2 minutes and than gas and oil (mixture) was blowing out of my breather line next to carb. Engine than started to run poor & shut it off. I checked the oil in engine and cranke case was now way above the full oil level mark by 2" almost. I drained engine and oil was like gas. I drained it again put oil in, took carb off and checked float and adjustment and seat and all looked perfect . Put it all back and started it up and ran about 2 to 3 minutes & did the same, started blowing fuel out of breather tube or crankcase rubber tube by carb. Did I rebuild the pump wrong to do this or what??? I have the fuel incoming line hooked in side of pump connector ,that is the right place for it isn't it? There is another hookup on bottom of pump that looks like it goes to engine. Should I just go buy a new carb or can someone help me. 
Thanks, John


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## Calcommon (Jan 27, 2011)

Fuel in the oil is a result of the carb float not shutting off the fuel flow when appropreate. It maybe a result of a poor seal i.e., float not adjusted correctly, corroded seat, mis match of seat and needle material, poor range of motion on the float, a hole in the float, or the use of a fuel pump on a carburator designed for a gravity feed fuel system.

I would start by confirming a good seal, with the bowel off, manually operate the float, while feeding fuel via gravity, very little presure is required to stop the flow. If it seals well, check the float for holes, if it does not seal well, insure you have a rubber tipped needle if you have a brass seat, or a steel tipped needle if you have a rubber seat.

Keep us posted.


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## dangeroustoys56 (Jul 26, 2010)

Id super clean the carb again and use a rebuild kit in it - good thing you caught it early or itd destroy the motor.

Ive gotten carb kits for like $20 - just write the motor numbers down and also how many screws the fuel pump uses ( if its the type attached to the carb).


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## Mickey (Aug 14, 2010)

My first thought is, is there a fuel pump on this engine that uses crankcase pressure to operate? If so, I suspect a diaphragm in the pump is leaking and gas being sucked directly in to the crankcase. Lots of engines use this kind of pump.


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## ronpaul (Dec 6, 2011)

Mickey said:


> My first thought is, is there a fuel pump on this engine that uses crankcase pressure to operate? If so, I suspect a diaphragm in the pump is leaking and gas being sucked directly in to the crankcase. Lots of engines use this kind of pump.


Mickey, your 100% Right! I took carb off and supplied water to connector on side of fuel pump and water came out of bottom connector on fuel pump. So thats when I knew it wasn't float seat. I took 3 bolt cover off fuel pump and found that when I rebuilt it last time I allowed the spring (bigger one) pull the diaphram inwards and making a bad seal, in other words gas went straight through the pump into engine. Good thing I decided to go on this forum, I was just ready to buy a carb, thinking i must have a crack in mine. You saved me at least 150.00. Thanks again Mickey & the others that responded. Wish you a Merry Christmas
from Crestview Fl.


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