Holley 1920 diaphram return spring

Killer6 said
First up, Yes it is most desirable to have two (or however many) identical carbs for multiple carburetion. There can be many differences in the same basic model carb that
have a large influence on the way it meters & delivers fuel, idle/main jets to idle/main air bleeds combined with emulsion bleed count/size/height(or lack of), design manifold/
base running temp calibration,high altitude/Cali/fed calibration, variations in power enrichment to main ratios, vacuum only vs vac/manual power enrichment, accel discharge
rate, volume, & timing,...transfer slot/port calibrations........etc...etc..........even two identical carbs have to be timed in sync to function optimally.....My '66 Yamaha YL1 has
a cool little 2 cyl. 2 stroke 100cc twin,...I can feel almost immediately when the cables let the throttle slides get a tiny bit out of sync.,..You can hear and feel it!
So back to Your second 3920, where exactly is the air leak,...around the shaft at the throttle body or...???

Well , that was a lot to swallow, thanks for typing it out. After running with both rebuilt 3920's it was the best it has ran since I got her , but the linkage was not pulling all the was back to idle , it would pull back to about 1/8 away from where idle screw should rest , and then slowly slow down to rest . so with engine off I tried to trouble shoot why - looking at the linkage of both carbs , the springs , everything looked like the pixs I took when I disassembled ? So I disconnected the linkage from the second 3920 ( front ) and the back carb worked correctly ( returning to ideal every time) Anyhow continuing to look for the cause of the hang up on front carb I notice a small amount of gas from the shaft where it comes through on the side where the linkage connects. don't see anything if engine is running , at idle, and not moving throttle , but with continued moving of throttle small amount of gas will appear . I will get a pix and post it