Wow! Steve! You were exactly right. One of the wires on the temperature sensor was disconnected...the screw had fallen out. I'm amazed I didn't notice that when I was looking at the exhaust elbow and trying to determine whether it was hot.
As I write this the genny is humming along, happy as a clam, pouring amps into the batteries and making water.
Are you going to be in Brunswick this summer? We're headed there in early July for hurricane season. Be nice to meet and buy you a beer or two!
Thank you for the help!
Outside No Name Harbor, Key Biscayne