Thanks for for that bit of info Bob. I had completely overlooked the fact that I had a manual for this motor sitting only 10 feet from me and I not once thought to look at it.
All of this is so new to me. Actually I did not know if the cables were matched to the boat or matched to the engine.
Yesterday I realized that the cables were OEM parts and designed to fit the engine and not the boat. So today I went to Green's Marine here in Wilmington, NC and to my surprise they had two 26' cables on their shelf. Evinrude Original Equipment no less and to top it off he gave them to me for 50 dollars each. That's like 1/2 price or better.
So I installed them this afternoon and had them hooked up with both forward and reverse working. After reading your post I made the connection that the cables were Evinrude and that I have an Evinrude manual and that I could look up the installation procedure and check the installation.
So now when I read the manual I know exactly what parts they are talking about and everything makes sense. Tomorrow I'll go out and double check everything. While reading the procedure that you suggested I also saw that there IS A WAY to further adjust the cable when there are no threads left. The shift arm on the engine can be adjusted if there are insufficient threads on the cable for the required adjustment... which answered the question to my original post.
Next project... change the rusted valve on the through-hull water supply for the wash down and live well.