That is a ground lug on the end of the black wire, not the round terminal that gets pushed into the carburetor. It sounds as if there may be a partial short circuit inside the carburetor between the two wires that should only touch when the speed control is in the stop position. The previous tenant may have disconnected the ground lug to enable the mower to run.
Does it run with that ground lug not grounded? If it does, that matches my guessed diagnosis on the previous paragraph. It means that one of the two wires pushed into the carburetor is out of position inside the carburetor.
Last edited by grumpy; 01/04/12 08:20 PM. Reason: Clarification
