Small Engines (Lawn Mowers, etc.): snowblower, spring problem, catastrophic failure

Question
i have a troybuilt 2410 snowblower that i bought brand new in january 2010. i used it all last year and once this year. the second time i went to use it it would start up and then die out after a few seconds and it was blowing white smoke. it was also leaking oil down around the exhaust somewhere inside. i checked the oil and it had a gas smell and i drained the oil and sure enough it definetly had gas in the oil. i put new oil in and it started and runs now but it still looks like it is leaking alittle oil. i havent snowblowed since i changed the oil so i havent been able to check to see if it stops. what would cause this to happen and is there anything else i need to do.

Answer
Don
What you have is a leaking needle seat in the carburetor,Gas will get into the crankcase when you have a carburetor that is leaking past the needle. This leak is generally caused by either a float problem or other problem keeping the needle and seat from sealing. If there is gas in the crankcase, then the recourse is a carburetor rebuild or replacement followed by an oil change. The reason that this is such a common Spring problem is that if you leave any gas in the carburetor, it will evaporate and leave behind a varnish coating that can prevent the float assembly from functioning. Also, and even more common, the ethanol in today's fuels will ruin needles and seats, preventing them from sealing the flow of fuel off, which causes the carburetor to overflow and leak into the crankcase. Gas can also get into the crankcase from a fuel pump that's leaking, so if you have a pump, that needs to be checked as well.
Do not under any circumstance attempt to start an engine with oil that fits any of these criteria. The most common cause of mid-size Briggs and Kohler engine catastrophic failure we see in the shop is from gasoline diluted oil causing the rod to overheat and break just above the crank journal.