problems with gas in crankcase

Q I have a 2006 Polaris Fusion 600. It worked fine when I put it away in the spring. This year when I can get it to start, the crankcase fills with gas and it stops running. I have rebuilt the carbs looking for any cracks, replaced the needle and seat, floats and rebuilt the fuel pump. I looked at the pulse line to see if gas is getting in that way and made sure there is no restriction in the airbox or exhaust. I got fresh gas, pulled and rebuilt the engine, and put a second set of carbs on. All that has solved nothing. Does anyone know what the problem is? – Allen

A Gas can only enter the engine in two ways, through the carburetor float bowl not sealing or through the fuel pump seals allowing gas to enter through the pulse inputs. Typically if the pulse lines are not soaked with gas, the fuel is entering through the carb through the needle and seat. This can happen from the float bowls not applying enough pressure caused by an incorrect setting or the buoyancy of the float bowls has failed from dry- rot or bad gas. – Jason Houle, Straightline Performance