[Adger Smith]

The fuel and timing go hand in hand. Watch the EGT's when working the fuel and timing. Usually, as you lean the engine it will want less timing to make power. When you have it fat it usually takes more timing to light the mixture because there is less air (O2) around the fuel. Same goes for more vapor pressure. It displaces the o2. As an example I'll try to post a PM I got from a racer I was helping tune in bad air. oops, Sorry already deleted the exchange.