Update: Pulling the powerhead was a good idea, but was impossible for me with my basic tools. There are 5 screws that come up from below the lower cowling which were easy to get to and remove, but there are 3 nuts on the top side (sides and front) which are inaccessible unless you have a flexible head wrench. So I gave up on checking the internal linkage of the shift handle rod. The handle was slightly loose on the external end of the rod however. I found that there is an screw and bolt that tighten the handle to the rod. In my case, the nut on the back side was completely off the screw and just stuck in old grease! There is an oblong opening on a small plate on the rod which allows adjustment of the handle with regard to the rod. See attached pictures.
There is also a second screw that compresses around the rod that was slightly loose. The connector of the 2 part shift rod in the middle of the lower unit was tight. I’ll have to try it once the test barrel won’t freeze and make adjustments as necessary. Thanks for all the advice. NABMD