Mariner 15 gear selector help

I have a Mariner 15 built between 94 and 98. The shifting mechanism on the tiller was extremely difficult to turn. I found that the plastic housing that the the cabls run in was cracked where the tiller shaft engaged it. I don't think this has anything to do with the hard shift but I replaced it anyway. What I did find was that the cam mechanism that the ends of the cables engage When tighten down puts a bind in the whole thing. If left lose everything works fine but this will not work as a fix as the cam would soon wear out wobbling around. It appears that there should be some sort of bushing between it and the engine itself. I don't beleive I lost it. Any help would be appreciated. Also, where can I get an engine repair/maintenece manual or a parts blow up of the right side of the powerhead.<br />Thanks, ****