I have one and wondered the same thing. It gets much better as it breaks in. I was more concerned with the engine going super rich as you raise the nose---as in on take off. The plane will not climb at a steep enough angle on take off for this to be a concern. I have not had it go lean from making long dives either. I think it might have something to do with the G-forces keeping the fuel pretty steady and it doesn't really know its diving as long as you are pulling a bit positive. Again, break in is the key. I ran 6 or 8 tanks before I flew it, and even then, it got better with each flight. I switched to a OS 8 plug to get a better idle. It does not idle low at all, but you will not need a low idle.