There is a fuel solenoid on the bottom of the carburetor. hold a finger on it. Have a friend sit in the seat, push the clutch/brake and turn the key to ON. Can you feel it click?
If not, its stuck and they usually stick closed. this is a common problem on that engine when allowed to sit with old gas in it. Old fuel deposits cause them to stick. I recommend replacement, as if you free it up it will usually stick again pretty soon.