Put a piece of fuel line on and carb fitting and blow. If air passes the carb is the problem and it is flooding while you are fueling. It most likely is the problem since you are getting fuel in the exhaust. Other end of the spectrum is that the t is allowing a lot of air in the line and it is taking a lot of flips to get the air out. A good carb will fill the fuel line in 4-5 flips. The air bubble should never move back towards the tank after a flip.. Watch what the fuel in the line is doing when you are flipping it will probably tell you whats up. Also you could pull the plug and look after 10 or so flips to see if gas is running out. Either way you most likely will need to clean and rebuild the carb..