Re: 1994 Mercury 40HP, No reverse
I was thinking along the same lines as far as making a tool out of plumbing. I priced buying a tool, but at about $80.00 for hopefully just a one time use, I had to balk. I bought a tabbed lock washer to hopefully use for that purpose that goes just on to the inside of the nut since I noticed it had at least three tabs on the inside, I thought I could bend the tabs inside of the nut and at least have something made out of metal to destroy. But your idea sounds much better.
The retainer nut on mine would have had to back off on it's own in order to be my problem and as hard as it was to get started turning I really doubt that happened. If I remember correctly, you don't know the history of your boat so someone before you may have not got it tight enough. Shimming in some way might do in either case it since our problems sound similar.
My dad has more knowledge as far as engines than I'll ever have, and has several people to fall back on if he ever gets stumped. He called a repair guy for me today at a local boat dealer who suggested my likely problem was in the shift cable binding either because of binding from age or possible internal fraying which would limit the travel. That's where I'm leaning at this point since I've also found a service bulletin on cable problems for several models and years besides and including mine since I first posted. Not for fraying, but a critical adjustment. When that possibility was mentioned it reminded me that in this off season I notice the box with my shifter was loose on it's mount by just a tiny bit. So it may be possible that a loose shifter allowed just enough slop in the action or throw of the cable to cause less travel and possibly not fully engage the reverse. You might look your cable travel over really close. It should be easier to tell if that's a possibility if you still have the gears out.
And the thought crossed my mind about cleaning up the edges of the dogs with a Dremel since the damage looked so minor, but I managed to find the clutch and gear on ebay for less than half the going price of boat shops. While I consider myself an above average tinkerer, I may be overestimating myself when it comes to marine problems and decided it wasn't worth risking having to do the job twice or more if I got it wrong. If I did that and still had problems afterwards, it might lead me away from the real or original problem and bring me back to thinking that I didn't get them ground just right.
Ten years younger and I would have probably risked doing that. But then, now I know I'd have at least ten more years to try to get it right. If it was my truck instead of a boat I'd do that. It's much easier for me to walk home than swim home to where I live. (Actually, it would be easiest to snowski home tonight) Almost summer and all I can do is talk boating since it's below freezing in a snowstorm tonight.
Thank you for your help!
Take care.
