I have recently recieved a 1980's-ish 25hp mercury outboard (remote controls) for free. I was told that it will run great but will not go into gear. It was explained that there is a "shear pin" in the engine somewhere that breaks when thrown into gear too hard so that it won't blow up the motor. Does this sound legit and/or is it an easy fix? Or do I have an engine now that won't take me anywhere?