Small Engines (Lawn Mowers, etc.): Carburator floods and gas gets into engine oil, briggs and stratton, pin holes

Question
I purchased a 2005 Murry with a briggs engine, from another person. The carburetor floods without the engine running. Gas gets up into the air filter and into the engine oil.If you start the engine it will run for about a minute and will flood out and the oil has gas in it. Do you have any idea what may be happening.  It is a 2005 Murry with a briggs and stratton 12 and 1 half Horse Power. Model number 28V707 Type 1113 Code 010316Z0

Answer
The float needle valve is not sealing or the float has a small hole in it filling with gas and is sinking instead of floating and pushing the needle back up into the seal the old metal type floats are notorius for this, allowing gas to freeflow through the carburetor filling the cylinder and then leaking past the rings into the crankcase. First try removing the bowl from the bottom of the carburetor, clamp off the fuel line first to stop the gas flow. The plastic or metal float is held in by a small pin you can remove this and the bowl will come out along with the needle. pay attention to how it comes off and it should be relatively easy to put back on. when you pull off the float check to see that it is not full of gas if it is then it is sinking instead of floating this is most likely the main problem and the float needs to be replaced if the float is not full of gas then try cleaning out the hole that the needle slides up into with compressed air and or carb cleaner and since your in there clean out anything else such as small pin holes even the nut in the bottom that holds the bowl on has some small primer holes in it. you may have gotten some debri stuck up in where the needle valve seats into the o-ring. after you put it back together fill it with gas and let it sit 15 min or so to see if the gas starts leaking out the air intake that the filter covers.  If no leak then try starting it but be sure you have changed the oil first, and you may want to clean off the spark plug as well. After running it a few minutes without the filter in a clean enviroment, shut it down and let it sit again. If no leak then I believe you fixed the problem. Let me know how it goes. These are the first steps I take when working with this type of problem assuming internally the carb is in good condition free of rust or corrosion. let me know how it works out