1. From 1/2 to 3/4 throttle, the additional flow of air is regulated by the slide cutaway. As in the mid-range system, the cutaway directs air downward over the high speed needle jet, limiting the amount of vacuum formed over it. As the slide is raised higher over the needle jet, the air passes more directly over the top of it, creating more vacuum, thereby drawing more fuel.
112 to 3/4 Throttle: Slide Cutaway and High
Speed Needle (Fig. 131)
2. The amount of fuel at this point is regulated by the high speed needle and needle jet.
3. You can vary the mixture from 1/2 to 3/4 throttle by using a slide with a different cutaway, but this will affect the mixture from 1/8 to 1/4 throttle also.
4. You can vary the mixture at 1/2 to 3/4 throttle by changing the high speed needle and needle jet. Again, this is impractical due to the limited selection of these parts available.
5. It is best to vary the mixture at 1/2 to 3/4 throttle by raising the high speed needle to richen the mixture and lowering it to lean the mixture.