I have a Champion 4000/3500 with a Chonda 196 cc engine. It started with 10w-30 M1 HM but has been switched to 5-40 RT6. This unit hasn't been called upon to save our bacon in the last six years. I believe it has between 50 and 80 hours on it.
I also have a Predator inverter 3500/3000 unit...