Forward instantly shifts to reverse??? No neutral

[Migillicuty]

So I got my 1984 mercury 4.5 lower unit put back together. As I assembled it I made sure I was able to twist the shift shaft and see that the prop shaft would go into forward, neutral and reverse. However, as soon as I got to installing the spanner nut until it bottomed out and lightly snugged it up, It now has no neutral. As I twist the shift shaft it goes from forwards and instantly switches to reverse skipping neutral. So I started to back off the spanner nut until I found a sweet spot where I had forward, neutral and reverse but it made it so the prop shaft had play. Not sure if this is engineered this way but I dont see any other way to make it work? If prop shaft play is normal and you have to fine tune that spanner nut then I guess I stumbled on to the way things are. Just want to make sure this is normal? That little shift cam had the littlest little steps on it making shifting sensitive. When I found that sweet spot it seemed like the prop shaft play was like a 1/8" play total in and out which seems excessive to me?

 

[fitz73222]

It is not engineered that way.The spanner nut is to be tight, like a good tap fit with a mallet. You have shims in front of the bearing carrier for proper reverse gear to pinion lash. I suspect you have damage to the shift cam from the engine being shift into reverse without the propeller spinning or the engine running. When you had it apart did you inspect the spring, and clutchdog cross pin in the propeller shaft for damage or binding? You created a new post about this; in the other post, I asked you to produce a photo or explaination as to how an extended drain plug screw created shift issues for which you said was the cause and had pictures? Just trying to help. I'm familiar with these gearcases.

 

[Migillicuty]

So after inspecting a diagram of this gear unit I found that there is supposed to be a spring behind the cam follower which I did not see as this came apart. After looking up parts I found it's called the cam follower compression spring. Looks like no one sells them either. I had a guy on Facebook let me know he has a used one. Part number 24-96298. So I should get that in a few days. That should be the issue with the shifting. The drain screw I had, has this magnetic protrusion that literally went in about centimeter in too far right is the pivot pathway of the cam as it twists. The seller on Amazon simply miscategorized this plug for this motor. I found other listings that have the very shallow plug which I'm sure is the right one now.