I bought one second hand, hand only a few dyno pulls on it. I installed it and cannot get it to run. Mixture screws do nothing, I can get a rough idle by opening the butterflies way up. It's basically running on the transition slot. It's a 2 circuit although these can be 3 circuit. I'm about to pull it down and go through it. But looking at it I have an air bleed question. It has 12 being 4 barrel, 3 circuit body.

Looking at the top down view below (not my carb I pulled picture from Holley website) mine has the exact same air bleed layout. That is outer most bleed is a solid blank. Next to it's another bleed then closer to the vent tube is what I understand to be the HSAB.

But, my understanding is that it's always idle air bleed is the outer most bleed then next to that, essentially in the middle is the intermediate bleed and then closest to the vent tube is the high Speed air bleed. If this is the case, why would the Idle air bleed have the solid and the intermediate not. Or on these FX series is the idle air bleed the one in the middle? Thanks in advance.

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