ok, cleaning these 34mm mikuni carbs up for a friend and I evidently lost the spring for the air screw. I have another here that I can put in (same screw), but I was wondering what the use of this screw was,,,,,,

My guess is that it does nothing more than keep tension on the screw so that it doesnt move around and end up falling out and flooding the carb with air,,,,in turn causing a lean burndown,,,,

am I close???

yes, what are these out of?

I had a buddy bring his ol JD liquifire over and asked me to help him get it running,,,,,, he said they were running it last year and it died and they couldnt get it to restart,,,they had the exhaust pipe and carbs all off,,, air box out,,, wires unhooked,,,couldnt figure out what was wrong,,,, I noticed that the pulse line for the fuel pump broke,,, compression was good, so I figure all that was wrong was this broke and it basically ran outta fuel,,,,

wouldnt that be nice!!!!!