I'm not familiar with that boat in single screw, but I assume the shaft will not clear the rudder? If not you'll have to drop the rudder making it a much bigger job. I have no idea how to do that on your boat. Inside the boat you remove the four coupling bolts and slide the shaft back as far as you can. Look inside the coupler, if there's a big nut in there holding the shaft in you've lucked out. With the nut removed (and any set screws, there shouldn't be any) with a few good hammer taps on the body of the coupler it should pop off. If there's no nut it's a press fit on the shaft and can be very hard to remove. Remove all set screws, cross pins, and anything else holding the coupler on. Give it a couple taps, if it comes off very easily it's probably shot and you need a new shaft and coupler. If it's tight you'll have to get creative. Most common is to make a jacking plate which is like a dummy coupler which you bolt onto the shaft coupler with a spacer in between that forces the shaft out. A wrench socket a little smaller than the shaft works well. This won't be easy. You could just use longer bolts and the trans side of the coupler, but you risk bending it's flange. That would be very bad, I don't do it that way. Some pros just use a sawzall and cut the shaft. The labor to remove the coupler can cost more than replacing it and the shaft. If you knew you were replacing the shaft anyway, by all means just cut it. Takes 20 minutes. You might want to consider that, there's no guarantee the shaft can be straightened or that it will stay straight. Bending it once has already weakened it.
