When you turned over the carb it probably drained the fuel out of the accelerator pump well and the rubber plunger may have just folded back and now dosen't seal. May try pulling up and down by hand to get it to reseal back in place.
However if fuel is pouring in you must have float problems now and will have to remove the top anyway to see what is going on there.
If you remove the top be v-e-r-y carefull. If you turn it over a steel check ball will fall out--pay attention where it goes--back into the accerator pump well. Been there done that.