Small Engines (Lawn Mowers, etc.): Briggs & Stratton 15A114, fuel in crankcase oil, briggs stratton, crankcase oil

Question
Hi Eric, Briggs & Stratton 15A114-0342-E1,code 051108-F6 on Craftsman model 536.881851 snow thrower. Engine has 10-12 hours of run time. Fuel is transferring into the crankcase oil. During shutdown flames will come out of the muffler. This unit had the required manufacture update due to a fire hazard. This problem occurred after update was performed by Sears. What do you think is the cause of this fuel/oil issue?  Thank you for your help.

Answer
A common cause for the problem you described is due to a leaky carburetor inlet needle seat.  The engineis an 2005 model, so I would suspect the inlet needle seat needs to be replaced whether or not you have used the engine.  The inlet needls are made of a rubber type material which just ages and turns hard with time.  Sometime moisture or debris get in the tank and can cause a leak.  Either way you should change and refill the engine oil as well as cleaning the carburetor.  Since you are cleaning the carburetor, I would replace the inlet needle and seat...cheap insurance.

Let me know if this helps.

Eric