Used John Deere turf guard 10w-30 since that was the first non synthetic 10w-30 I found in my shed. Put in oil and gas and started it up. Plugged in the heater and fan that should be around 1600 watts and let it run a few hours at full throttle. With the eco throttle on it was about half throttle with that load.
8 hours run time isn't going to be acceptable. Gonna get one of those extended run tanks. My 8000 watt generac will run 24 hours on a tiny load. The EU 3000i I have won't even do that.