Again, after about ten minutes of the engine running, I shut down for a few minutes. Turned the key to restart and just cick, click, click. Removed the engine cover thinking it would cool the engine quicker and waited ren minutes. Fired right up! Ah Ha, engine heat. Problem solved ... NOT!
Ran the engine with the cover off for about five minutes (I was spreading mulch) and then shut down again for about five minutes. Turned the key to restart ... click, click, click. Waited ten, fifteen minutes for the engine to cool further. Still just click, click, click. Jumped the mower battery from my car battery and it started right up. Mower battery still shows 12.7 volts with engine off and drops to about 10 volts when clicking.
I'm thinking new battery.