Float is stuck. For a temporary fix, rap on the front top of the carb with the plastic end of a big screwdriver. They usually unstick like that. You may have to dry your plugs off to get it to start. Sometimes if you roll it enough without giving it gas it will fire after the plugs are flooded. If you don't want to take your carb apart and clean it then you can try some STP gas treatment to help clean the varnish out of the carb.