hi mate not sure what movement you,ve got but its impossible to overwind a clock, you can fully wind it and then it stops,threre will be a locking meck which stops the spring from unwinding if you disengage it from the toothed wheel it will unwind, be carefull as it does this at a terrific rate of knots. But you will have to look elsewhere to find out why its stopped
mike cox
October 2009