I have a Cris Craft i/o with a 230 V8 (305 cid) and Alpha One drive that I got from an Uncle that's been sitting for at least two years. When I push the throttle forward, I get a little clatter, but the prop engages and turns. I get nothing when I move the throttle back into reverse. Is it just a shift cable adjustment, or does the drive need to come off and be disassembled?