I don't know the factory settings, but I could give you a general base setting. I usually turn the high speed mixture screw out counterclockwise until it's flush with the needle valve. I do the same for the low speed mixture screw also and then I work the needles clockwise from there in small increments to achieve performance. I would advise to never turn the needles all the way clockwise in on any of the valves because that can damage the mixture screws ... I hope that didn't sound complicated ...