Cool!.....................i have the same boat, i bought it on e-bay three months ago. My reduction still works on mine, and i've converted mine to brushless, a castle 4600kv and a sidewinder esc..............it flys! Take the motor out, and take the reduction apart if you can, see which gear is bad and try to find a "standard type" replacement for any rc, truck, car, whatever. If not you can put a motor mount in it with some modification (some dremel cutting i would imagine) and simply put the drive cup onto the motor shaft. This may take some modding too, the drive cup may be 4mm or 1/8 etc........... . I thought of doing this at first, but since my reduction still worked great i went with my present setup. Its a real sleeper...............looks like an old, outdated boat.......until i hit the throttle and it jumps out of the water.. Let me know if i can be of any further help, i'm interested to see what you do to fix it.

P.S. - i had to manufacture my own dog bone drive to handle the power, that little red plastic one is pretty thin.