True. But if you'll note most of the time an inverted engine on the ground try to run rich. So it's leaned. Then when it's flying inverted, it's way too lean. The oppsite happens with an engine upright. When you invert in flight, it goes rich. Don't understand why so many people want to invert an engine. No other engine used for anything else is by design made to run UPSIDE down. Plus an engine design for a RC was not made to be. It's been the design of the makers of all these new planes that have caused this.