I downloaded the Solex manual but it is vague on the different model particulars. then it suggested the mixture screw on some models let in fuel. Does my mixture screw on the Solex H40 let in air like most mixture screws?
Also, does one have to jet the idle circuit just right to keep the carbs from popping while it's cold. I have no popping when it's warm just off idle.

It's an air bleed screw. As there are no chokes, cold running is always a problem. I've used Kadrons for close to 30 years, and have found they don't work all that well on T4 motors, BTW. Be sure the accelerator pump nozzles point precisely at the opening point of the butterflies. The Cap'n

Thank's Cap'n. I'll use these until I can get the dual 40s!