Try this logic...
If gas is running out of the carb in a steady stream.. then it must be coming into the carb in a steady stream... right?
Well... there is a device in the float bowl who's job it is to shut off the fuel going into the float bowl when the fuel reaches the proper level... it is called the float needle.
The fuel flows in... the float starts to float on the fuel, rising upwards till it pushes on the float needle, which pushes onto its seat, and shuts off the fuel flow.
So... something is stopping your float needle from shutting off the fuel flow.
There is either a piece of crud in the way.. blow it out (and get an inline fuel filter if there isn't one).
Or.. your float needle.. or float.. is 'stuck'... sometimes you can simply pick the rear tire up off the ground and drop it from say... 5 inches.. and it will 'unstick' the float.
Otherwise take the carb apart and check it out and reassemble it.. make sure the float swings up and down alright and the needle slides in and out of its hole alright.