$Rich$ : Yes, when it is idleing, I can push on the linkage and make it close and it idles right down. With the cable hooked up it does not touch the stop screw. Unhooked, it shuts by itself.
RTNmsds: That was my idea also. I pulled out the big plastic piece that goes down the tunnel, and pulled the cable out. It looks fine. The last six or so inches of the cable has a sleeve crimped on it that slides into a larger sleeve of the sheath, and bottoms out. I trimmed about 3/16" off the sleeve that is crimped right onto the cable, and that gave it enough to close all the way. The cable moves very freely, with no hang up whatsoever. Only thing I can think of is over the years, dust and dirt got built up inside the outer sleeve, on the "bottom out" surface?
84Bill: I thought of this, but when I checked it, with the cable pulled tight, there was still about a half an inch of cable before it bottomed out on the pedal. It was bottoming on the sleeve.
I hated to trim the sleeve, as there has to be a reason it got like this, but I can not find anything, other than a possible build up in the outer sleeve. Thanks for all the ideas guys. Any more would be great. Even though I have it working fine now, I would still like to figure out how and why this happened!