And please remember that the so called "factory carb settings" are only a starting point, and a setting that hopefully guarantees the engine will start for you. You MUST then tune it properly yourself. The exact needle settings you end up with will depend on your fuel, oil, fuel/oil mix, prop, temperature, barometric pressure, humidity, stage of engine break in, and the phase of the moon. People often tend to think that engines can just be run with the factory settings, but in fact, those are only gross settings that must be optimized by you when you run your engine.

When we tune glow engines, when we get close, the optimum setting is dialed in a "click" or two at a time. A gas engine with it's needle valves setup for a screwdriver are often over adjusted to the point of passing the optimum setting. The needles are sensitive, and when your tuning is close to optimum, a 1/8 turn of a needle is a lot. Often times just a screwdriver blades width of a change is all that is needed.

AV8TOR