Oil in Gas and Gas in Oil

[BigDaddyFatSack]

Hi everyone. I'm new so be gentle. Lol. In 1990 my grandfather bought a new Task Force I/C 12 HP 38" cut riding mower and gave it to me about 7 years ago. It has a B&S Model 281707 Type 0411-01 Code 89082511 in it. After it sat for about 10 years, I installed a new battery and cleaned out he fuel bowl and it has run like a dream ever since. Until last week. Started it one morning and it had a rough idle. Pulled the air filter and looked into the carb and it had what looked like oil and gas mixed cause it got dark quick. Throttled it all the way down and you could clearly see gas until it was throttled up and it filled up with gas and oil and then cut off. Today I took the head off and could see oil and smell gas on it. Rotated the motor by hand and watched the valves stems to possibly check the valve seats. The exhaust valve had very little on it so I figured it would be blown out anyway. The intake I couldn't really tell due to the gas. A short time later I checked the oil and noticed it wasn't as thick as it should be. Lit a lighter and the dip stick oil lit too. What would cause this ? The only thing I could think of was maybe the valve seats or the piston rings. Any help with this question would be greatly appreciated

 

[KennyV]

Problem is the float is Not completely shutting off the fuel flow when the engine is Not running...
The ultimate fix is install an inline fuel shut off valve between the fuel tank and the carb... You will Need to remember to turn that valve Off when the engine is Not running.
Change the oil, you will be set to mow... :smile:KennyV

 

[BigDaddyFatSack]

I'm not a lawnmower mechanic by no means but I just don't understand how that would help anything. How would that cause Oil to get into the Carb ? How would that cause Gas to get into the Oil ? How would a valve between the tank and carb solve a problem that wasn't there for the past 20 years ? I just don't get it.

 

[Carscw]

I'm not a lawnmower mechanic by no means but I just don't understand how that would help anything. How would that cause Oil to get into the Carb ? How would that cause Gas to get into the Oil ? How would a valve between the tank and carb solve a problem that wasn't there for the past 20 years ? I just don't get it.

Ok forget the valve and rebuild the carb.

When the engine is not running the neddle in the carb is letting the gas flow into the engine and into the crankcase.
Give the carb a good cleaning and replace the needle valve. Or as Kenny said just install a shut off valve in the gas line.

This has happened because the carb has got trash in it or you left gas in it over the winter while it was not being used.

(( racing is the only sport that you need two balls ))