Hi guys
I want to thank you for your answers and am grateful for this forum. I had many other more pressing things to do but finally got around to fixing the mower. The yard now looks groomed.
Muddin thought it might be the armature and you may have been right. I bought a new armature and asked the service rep about setting the timing. He confirmed scott痴 answer that it is the key-way. The flywheel was tuned about 100 past its position.
The nut came off without difficulty but the flywheel was another matter. No matter what I did, it did not budge. I watched some videos and none of that worked for me. I finally made my own tool.
I had a 1シ by 5/8 steel bar. I cut an 8 length and then drilled 3 5/16 th holes 3/4 apart. The holes that I had to tap on the flywheel are 1ス apart. I tapped the center hole for a 3/8 th bolt. Next I fastened the bar to the flywheel with シ inch bolts and the used a 3/8 bolt to start pulling on the flywheel. With a little prayer it finally came off.
Last time it cost me $300 to get the mower working. This time it only cost 60 bucks for a new armature and and a little effort.
Thanks again for your valuable suggestions.