gas in oil

[mowerman186]

I keep getting gas in my oil. Have a Briggs & Stratton Engine with 19.5 When carb is off engine I can put a short gas line to gas inlet and carb up right and blow into it it. Turn the carb upside down and can not blow into it. It has a Nikki Carb on it. I have cleaned the carb and have checked to make sure the fuel solenoid is working. Even took it off and checked that way. It is moving up and down when I turn key to on position. I work on small engines as a hobby and have run into a number of these. What am I not seeing?

 

[ILENGINE]

Make sure the float doesn't have gas in it. The other thing to check is make sure the vent for the carb bowl isn't clogged. if it is will cause siphoning.

 

[mowerman186]

Make sure the float doesn't have gas in it. The other thing to check is make sure the vent for the carb bowl isn't clogged. if it is will cause siphoning.

I did check the float and there is no gas in it. Now... where is the vent for the carb located ? I did do this... I loosened the bolts hold the carb and slide the carb back just a little... hooked the gas line back up... and watched to see if I could tell where the gas was coming from... the brass tube inside the carb...
I believe is called the ventura... gas was coming out of the top of that tube... thanks for the reply.

 

[ILENGINE]

The recommendation from the engine makers is to hook a pressure pump to the fuel inlet, turn the carb upside down, and apply pressure through the fuel inlet, and it needs to hold at least 2 psi for 1 minute. sounds like the needle valve isn't actually sealing correctly.

By the way I have done the above test, have it pass, then install the carb on the engine and turn on the gas, and get the same effect that you are having. Just had a Honda GC190 last month that I could turn upside down and pass the test. the float was good, but you could install it on the engine, and crank the engine twice, and the fuel pump would overfill the carb, and blow gas out the air cleaner. had to replace the carb.

 

[davbell22602]

I got a Briggs also that has the Nikkii carb as well. After the engine shuts off then I here gas filling the crankcase. New carb is $150 but it subs to the walbro as Briggs doesnt offer the Nikkii carbs anymore. Will put a rebuild kit and go from there. Just saying.....

 

[briggs]

I keep getting gas in my oil. Have a Briggs & Stratton Engine with 19.5 When carb is off engine I can put a short gas line to gas inlet and carb up right and blow into it it. Turn the carb upside down and can not blow into it. It has a Nikki Carb on it. I have cleaned the carb and have checked to make sure the fuel solenoid is working. Even took it off and checked that way. It is moving up and down when I turn key to on position. I work on small engines as a hobby and have run into a number of these. What am I not seeing?

rebuild the carb or replace it i would install a inline fuel shut off as a fail safe in-case this happens again ...Much rather have a fail safe then a big hole in the block then its useless

 

[Grassbandit]

I had the same problem recently and to solve it I used a fuel shutoff valve. So when I'm done mowing I just shut off fuel flow and let whatever's in the carb burn off so the engine idles down. Alot easier than going through the trouble of a carb rebuild and messing up your freshly changed oil.

 

[timoth]

I'm having trouble with gas getting into my oil as well. Murray lawn tractor with B&S 16.5 hp engine. Can this problem be caused by the after-fire (fuel) solenoid not working or does it usually mean the needle valve?