Originally Posted by
thepamster
Glad you gotter goin' Bob.
Anytime you change oil brands, ratios, gas type, or props, a slight change in needle settings may be required.
This also applies to a change in seasons sometimes, though not always.
Happy Flyin'.
My guess it has to do with the viscosity of the mix. If one mix has a higher viscosity (thicker) than the other mix, the amount of fuel that passes through the tiny openings (jets) will differ somewhat. A thinner viscosity will pass more freely ...so you may need to set the mixture more lean in that case. Does that make sense?