I have a 2003 Fisher 1754 CC with a 2003 Mercury oil injected, 2 cycle, 3 cylinder, 40 HP motor. I was on the river yesterday and turned off into a side creek and just came off plane when there was thump when the boat hit something followed by a big bang as the motor hit whatever it was. The motor did not die. I started back for the ramp and there was some vibration so I knew I tore up something. As I turned into the creek where the ramp is the motor would not shift out of gear and the motor started revving wide open. I turned off the key and got to the ramp with the trolling motor. When I got the boat back on the trailer and was able to check it out there was a gouge and a dime size chunk broken out of the skeg. One blade of the prop was chewed up and about half of it was gone. I tried to shift it and it shifted back to neutral. I spun the prop and it turned OK. It now shifts into both forward and reverse. There are no visible cracks in the lower unit and no leaks. I can repair the skeg and get a new prop but I don't know what else I tore up. I don't know why it wouldn't shift and revved wide open when I slowed down at the ramp and now seems to shift fine. I haven't started it yet but don't want it to immediately run wide open running of earmuffs and blow up. Besides the obvious damage to the skeg and prop what else should I look at that I might have damaged?