The secondaries on my AFB won`t open properly or rather they open only randomly. Mechanically, all is loose and moving freely. However, the secondary shaft is blocked most of the times. From my understanding two things need to come together to open the secondaries: 1.) the choke valve needs to be open, 2.) the primaries need to be at WOT. When the choke valve opens and the choke valve shaft turns, it moves the fast idle rod on the throttle linkage side, pushing down the fast idle cam which releases the lockout dog. When the lockout dog swings down, it gives way for the tang on the secondary throttle shaft, allowing the tang to pass the notch in the lockout dog and the secondary shaft to turn and open. The lockout dog - from what I see on my carb - is only moving by gravity, hence no spring, lever or linkage. Is this correct? On my carb, the dog swings down only a bit, not completely, not wide enough to let the tang pass. Any ideas why this might be the case or if there is something missing or worn? The linkage assembly has a spring for another part (underloader?), which is not very stiff, could this have anything to do with the secondaries not opening?
I bent the fast idle rod to a wider angle, that helped a bit. Can the choke spring develop sufficient tension to open the valve completely when the engine warms up? I’ll see once the carb goes back on. On the auxiliaries, are those solely ventury operated, without any sort of mechanism?
