yes that is pretty common for the AP plunger cups to dry/shrink. Luckily new ones are cheap just gotta get the right one and they can be hard to find on occaision EDIT If this is an OE AVS which will have 3 step rods/tall pri jets you can get an Eddy strip kit (2 step/short jets) so you can play with the main metering as all OE AVS's were emission era carbs & will respond good to tweaking. Pick the performer strip kit with sizes close to what the AVS has