Yep, thats the one. It wont stall the bike if you turn it all the way in. But it will run starved at idle & hot. This screw adjusts the pilot mixture... so it affects: starting, idle, going on to the throttle 0 to 1/4 or so (overlaps with the needle) and coming off the throttle.. hence it stalls when you come to a stop (closed throttle bog). At least this is what i think. Ace outlined the condition above. Ive attached more details below on the carb and its function.
So, I'd start back with the screw in the original position (did you remember that? 2 to 3 turns out from full stop if on stock pilot jet). Warm up the bike, and screw it in say 1/4 to a 1/2... leaning out the circuit. Then do test ride to see if it still stalls. You shouldn't hear any pinging or popping in the exhaust (indicating too lean or an exhaust leak). Also, may want to try bringing up the idle a bit. I find my electra likes a slightly faster tickover. If done right, you wont stall, and should need the choke at startup.
Theres lots of information on this forum on tuning carbs; specifically in the AVL section. Have a search.
Hope this helps and let us know if this works.