Anniversary clock, new suspension wire only runs ~10min then stops?

It had been severely overwound so I ran it forward ~72hrs using minute hand then slightly released pressure off locking mech. & slowly let the spring unwind. Everything is calibrated as in the forks & all.
It sat for years with no wire so I got the required wire, blocks & fork assy. Put it on & found it'd run for 10 min before stopping. Released the spring tension & wound it ~2 turns but it still runs 5-10min before slowly stopping.