accelerator pump arm

hi i know theres been many threads on this but can find exactly what i need to know, lately been having problems with my car hunting and running lumpy, today started the car and the car wouldnt idle less that 2000 thought choke was stuck but wasnt and on further observation noticed the throttle linkage wasnt fully shut off so idle screw was touching the base so kept having to do it by hand. but as moving the throttle by hand then letting it back to idle noticed where the accelerator pump arm goes into the side of the carb that can be bolted off that holds diapragms noticed the arm kept sticking . this is hard to explain on here but its the drivers side of the carb there is a thin slot where the accelerator pump arm sticks out slightly and rocks as you move the accelerator arm from under neath.should this bit be stuck out slightly of flush in when its on idle.sorry this sounds a muddle will try and explain better if no one can understand thanks