I have a 69 100 hp Merc. I bought the motor for the power head and was told the lower unit would not go into reverse. Not knowing how they work last winter I decided to tear the lower unit down to see if I could spot something that seemed to be a problem and see how the unit worked. Everything in the unit looked great and the po had told me that he had it rebuilt about a year and a half before it quit working. I replaced the shifting cam in the toe of the unit and everything seemed to work like it should. I installed the motor with the lower unit on my boat this spring and all seemed to work fine the first time out but last time it got so it would not go into reverse, it would just grind. I have a friend that has worked on quite a few of these old Merc engines and he thought it was probably an adjusting issue. We have adjusted it as far as we can on the shift cable and it will now engage but not without grinding hard each time it is engaged. Is it a possibility that something in the linkage to the lower unit or engine could be off a cog or something? I can't see how that could be but I am a long way from being a mechanic. I just like to fiddle. Any ideas would be greatly appreciated and thanks for all of the help that you guys and gals are to us novices.
