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Finally took my carburetor apart and found to much play between the main setscrew and the aluminum body that housed it. Also the ball on the end of the setscrew was to loose in the needle holder socket. I calculated that there was over a 1/2 turn of play and 1/8 adjustments weren't getting it.
In the side of the setscrew I drilled a 5/32 hole, forced a nylon pin in the hole and cut the ends of the pin off at the outer thread dimension creating an interference fit between the setscrew and the housing. I shimed the ball joint/socket housing and got rid of that play also. This gave me 1/8 turn adjustment that worked. Hope this 30 minute project helps some one.

You have discovered the same thing I did a year ago. I and another Onex bulder in Tenn. have been doing carb. needle research for about a year. First the needle holder has too much play in it. We made new ones with a disk instead of a ball. Zero play. Next we started making needles to get one that did not require a lot of mixture adjustment during a normal flight. The end result is what another Onex owner in Florida did. He is using needle #3. What you say. Why would I want to go to a richer needle? I'll tell you why. The slope of the #3 is higher and as a result the wot sweet spot, about .085 thickness, is closer to the idle sweet spot, the end of the taper. This means when you are adjusted for wot, the idle sweet spot is within the diameter of the carb throat. In my case, I marked the needle on the bottom with a file so it can be easier seen and more accurate than a felt tip pen. Install it until you can just see the file mark. Then adjust 2 1/2 turns leaner, clock wise, and try it. I get wot with about one inch of mixture and I don't have to change it during flight or after landing during taxi. Before you give up on the AeroInjector, try needle #3. What do you have to loose?