Here is a wierd question for ya. I have a Buggy B9 freshly broken in so its still set fairly rich. I ran a half of a tank the other day and set it on my bench. I did not burn all the fuel in the engine nor did i remove the fuel from the tank. I capped the exhaust and set it on the bench. Today I vent out to empty the tank, burn the fuel in the engine and add after run oil. When I pulled the airfilter of it was soaked with fuel and fuel went everywhere and the carb was full to the top with fuel. I no its probably no big deal just curious what physics caused this, me capping the exhaust nipple? thanks