1991 70 hp jumping out of gear??

[ric67]

i've got it apart and the dog and gear have some wear but is it enough to make it jump out? is the shift rod adjustment maybe some of the problem?
and does anybody no the spec for this? one more ") i'vegot about 20 thousands end play on the drive shaft. is that normal or do i need to remove the one shim i found in there.
thank you