TMD may be right there lemon aid. But just to be sure.....disconnect the shift cable and shift it into forward manually at the engine and see if the problem persists. If it does, gear work is in your future. If not, make sure the control box is in neutral, spin the prop and make sure the gear case is in neutral. Adjust the thumb knob on the shift cable to knob retainer with just a little forward tension....just a little. This should put the shift cable in the right place. Also.....


Have you checked the gear lube for any bits of metal or just to see if it was good?


And by all means....get the manual as roscoe suggested. Loads of nifty stuff in there.
__________________
When in doubt...use the manual
Rayland, Ohio....Along the Muddy Banks of the Mighty Ohio River.