That's how I've always understood how the dang thing works. Thanks Map.Nope, well said, you did a good job brother.
I call it a low speed mixture needle, that is precisely why it has notches and a clip to raise it just slightly while at part throttle so the amount of fuel the engine gets is limited until the engine revs and is able to get more air flowing in, to me its similar to a regular flow control needle on an old briggs or tecumseh carb but the difference is that on the slide carb its variable.
Im not saying that my opinion on this is 100% correct but this is how I understand it and 8 know that needle does very little of anything once it moves a particular distance from the main jet because more fuel cqn flow around the needle in the emulsion tube that can actually even be pulled through the main jet, this is what makes it a non factor once it moves so far up away from the main jet, it no longer restricts the fuel flow since it will allow more fuel to pass then can be pull3d through the jet.
Dang here I went and gave more $ .02 than I had intended.....lol!!!
fatdaddy.