Just got a 9.9 horse Gamefisher. It runs fine but won't shift. I took apart lower end and found a bunch of needle bearings loose in gear case. Also one tooth gone from the gear that comes out with the prop shaft. It is a Model 217-586231 (and perhaps one more unreadable number) and Serial # 9A-335879. I need a lot of help. First, what have I got? Are parts available? Or should I remove power head and sell it?