4 spd. pops out of gear.

Alaskan_TA said
Common issue.

Adjust the linkage per the directions in the FSM for a baseline.

If it still happens, move the adjustable swivel in or out one turn, try it again.

I have not had one yet that took more than two turns.

I`ve checked linkage alignment several times to put that out of the equation.
What are you trying to achieve here? pulling the gear more in mesh or to it`s limit/ stop point?