Re: 65hp mercury bottom end
Are you talking about the piece that slides down over the shift shaft and has a tapered edge around (sort of looks like a road winding up around a mountain)? If so, this is the piece that controls the reverse lock on the motor. There is another rod that extends down from the upper unit that sits on top of the piece described above. When you put the engine in reverse, the shift shaft rotates and that piece forces the reverse lock rod up, thus engaging the reverse lock. Therefore, it does need to be on a specific way. Not sure where exactly it should sit in neutral, but should be obvious how it should sit when in forward and when in reverse.<br /><br />Maybe someone else has a diagram or knows for sure how to set it in correctly...again, assuming that is the piece you are referring to.