If at first you don't succeed, get a bigger hammer! I was able to drive the key out using a 3/16 punch and my 3 lb mini sledge hammer. Kind of nerve wracking pounding on the key/propeller like that. I wound up wedging a 2 X 6 between the ground and the underside of the prop shaft, right against the webbing of the prop. Of course I was swinging the hammer right next to the rudder as well! All's well that ends well I guess.