Hey guys, here is the current update. One of the members, Chris, is being extremely supportive, and has offered many suggestions by phone. At daylight on Sun. morning, I went out and checked the machine over. The first thing I did was disconnect the batteries, and noticed that the ground on the battery was warm I checked the voltage on both the batteries, and they were slightly down, 11.something V each. I removed them from the generator and replaced them with a pair of fully charged batteries, 12.9 V+ each. On connecting the ground, that terminal arced. So the batteries were removed from the generator, and then I removed the starter motor. Cleaned all the terminals really well, and installed a new starter motor. Checked and cleaned the grounds to the chassis, motor, etc. and re-installed the batteries. On connecting the ground to the starter, this time there was no arc. I thought I had got it.
Went to control panel, and, yes, the control panel lights came on. Moved the master switch to prime the pumps, and everything started up. Beautiful!! Started the generator, and yes, it fired straight up. I allowed it to warm up, and threw the transfer switch and it started operating the whole house, drawing about 17% of capacity. It ran great for about 15 minutes, and stopped cold. Same disaster.
Instantly turned the master switch off, and removed the ground from the battery. The only difference this time is on reconnecting the ground, there is no arcing from the battery to starter terminal.
So now the batteries are disconnected, and my intention is to take the first starter motor into the shop tomorrow, and have it overhauled/rebuilt. Fellow member Chris has suggested adding additional grounds, engine block to frame, frame to battery, etc. which I intend to do as soon as I am able to get another known working starter.
Guys, every bit of input you've helped me with is greatly appreciated, and Chris, thank you so much for your phone assistance and help especially. I can't afford to burn up starter motors every time the power goes out!
We'll keep you all updated.