$$$ Update

A couple of the problems I mentioned yesterday are on the way to being solved.  
We found someone to take down the big tree in the back yard, and he helped me get the starter out of the mower.
I was able to determine that the starter needs a rebuild - bushings are worn and. although it spins on the bench, it binds up when on the mower.  I called the dealer, and after three trips to the garage for serial numbers, he said a replacement starter would cost $235 plus tax, and he would have to order it.  I found the same starter on line for $134, and ordered it.