Sounds like the float valve in the carb is leaking and was it replaced to and its brass seat tightened securely? Sometimes the float will hang-up on the bowl gasket to, which requires trimming the gasket a bit. If the motor won’t crank over now, either the battery is dead or one of the cylinders may be full of gas and it’s hydro locking. Best to pull the plugs, ground the leads and try cranking it over to dry out the cylinders.
Also, make sure the bowl vent isn’t plugged. Small insects like to get in there and build a nest.
