Even though you have installed a repair kit in the carb, the float valve isn't sealing for some reason. Could be a burr on the float valve seat or something else causing issues. Also something else to check is the vent that goes from the side of the carb intake to the bowl(normally the largest of the two or three holes on the side wall of the carb venturi). If the bowl vent isn't open it will cause a siphoning effect and act like a float valve not sealing. Make sure the float doesn't have gas in it because it will cause it to sink and not shut off the fuel when the bowl is full.