Two of the biggest problems I have found with Carter AVS carbs is vacuum leaks & poor parts availability.

Look for wear on stepup pistons, rods, the primary jets are most likely oversize/oval, the throttle shafts especially the primary is most likely worn & mayme the body of the carb. The hot air compensator valve needs checked as the bimetal strips fail, is this the valve that you think goes to a blind hole? it usually is open to the botton of the carb.

Only buy good quality rebuild/gasket kits, I have had trouble with sub standard gasket material failing with modern gas & the thick insulating base gaskets in some of the cheap repo kits are not worth a pinch of sh!t.

If you find a source for spare parts (other than rebuild/gasket kits) at a reasonable price please let me know.