Antique 8 day 8 inch Lever Waterbury Clock

Hi, I recently pitched this antique 8 day Waterbury 8” inch Lever Wall clock at a Rummage Sale I love this clock but unfortunately it’s not running ? When I try to wine the winding arbor it appears to be fully wound but when hung legal on the wall it won’t run (tick tick ) when I took the face off and add pressure to one of the gear wheels the key pointing to the gear it will run but when a let go it stops any one no what I can do to get running I can’t afford to get fixed thanks