[scootnwinn]

there are at least 2 ways. There is a screw on the bottom of the float bowl generally, unscrew it and see if fuel leaks out (sometimes there is a hose attached under there and the fuel will leak out the hose) Also pull the fuel inlet line it should have fuel depending on where your tank is located it will flow freely or trickle. If your tank is floor mounted check to make sure the pump works by cranking it while the line is disconnected it should squirt fuel. Some gravity feed tanks have a vacuum pet cock that works similarly.

You can also try artificially introducing fuel into the carb mouth to see if fires and runs for a moment. If it does it definitely has a fuel issue...