+1 what Abe said. No 4 is the fixed one, all others adjust to it individually. It might take a few iterations to get it close, and make sure you blip the throttle in between adjustments to make sure that the linkage is not affected by adjusting the screw. Sounds like 3 was way out, but once that is fixed the others get in on the act. I have the flow meter and the carbtunes, and each gets to the same point, the flow meter probably easier to use as the carbtune is too accurate so can make you frustrated with not being exactly right.