That's a cute little clock! Regarding "overwound", there really isn't such a thing. When fully wound a spring makes maximum power unless the spring lube has turned to glue and is creating "stiction" between the individual coils. If the clock doesn't run, most likely it's losing too much power to friction or obstruction, and/or the escapement is not doing its job. After you replaced the torsion spring, did you set the beat? That's the first thing to do. If that doesn't get it going, it will need a complete overhaul and mainspring service. The mantra here is that if you don't know the last time a clock was serviced, it needs it.
Thanks for all the help on getting the parts for this clock. I, finally, got it back together today. New torsional spring and pendulum ‘lock’. Of course, I didn’t bother to check the clock, itself, and now discover it’s over wound and doesn’t want to run. Sigh.
