riding lawnmower

18hp B&S engine with Nikki carb. Would only run if fully choked. Disassembled car, cleaned and replaced. New fuel filter. Drained old gas and re-filled with non eth gas.

Now, gas is mixing with oil. Not oil with gas. Gas in tank, fuel filter, and past the fuel filter is fine.

After cranking and running for a very short time, engine loses compression. If remove plug and or oil filler cap and attempt to crank, oil and gas mixture shoots out oil filler opening and/or plug orifice.

Clean out/burn off and refill with oil and new gas. Same thing. ????

 

Your carburetor float valve is sticking open or not sealing against the valve seat. That lets the float bowl overfill and flood the engine which fills the crankcase with gas.

Take off the bowl and clean the float valve the float works up and down to regulate the flow of gas to the bowl. You should be able to apply a small amount of pressure to the bottom of the float and stop the gas flow.

Also, check the float for either gas saturation by dropping it in a container of gas to make sure it floats or shake it and listen for sloshing of gas inside the the float. The latter would indicate it's leaking and needs replaced. A lot of times, it's easier to just replace the float and valve if attempts to clean them doesn't work the first time through.

After the carb is in good shape, change the oil in the crank before running. Make sure you have it at the right level.

 

Thank you very much! My neighbor thanks you also.

 

Ain't no problem. Hope it all works for ya.