The generator is an ST3 wired for 120v. I still have the doghouse on it and put a 20 amp breaker in it, along with a plug for the generator wire. That wire then goes to another plug on my power shed. From there it's to the AC panel. I've got a single, Outback inverter and 8 - 6v batteries at 24v for 760 amps total.
After my last message, I went back out and tried it again, using my portable breaker box and the kill-a-watt meter. I fine-tuned the governor to run at 61 hertz at no-load. Voltage was still around 137. At this point, I connected a 1.1kW load, which decreased the hertz slightly, but not too much. Voltage also dropped slightly. As for the engine, no change. I then connected the generator to the power shed outlet and got it to start charging the batteries. No error light this time.
Two things, I think I was too impatient. THis time I waited until the engine had run for a few minutes before trying to adjust the governor. Then, I spent more time adjusting the governor to be "just right" rather than "I guess that's good enough."
The engine has not been run often or for long. I suppose there's perhaps 30 minutes total time on it at the moment. See my other threads about cooling and fuel. I'm still not quite happy with my setup, but those things that I want to change are fairly easy. One is to get the Utterpower-style governor on it. It blows black smoke when first starting, but clears up very quickly. When I put the load on it, there was very little change in the sound of the engine and NO change in the color of the exhaust.