Very nice looking typewriter. I have a parts machine (Corona 3) and when I return I will see if it has the clock motor and if if does I'll contact you.
The word you're looking for is mainspring, I think. I like your solution of using a weight! Some of Sholes' experimental models worked that way.
My Oliver 9 mainspring broke, but luckily, it was only a half inch or so of the spring inside the housing. I opened that up, took the broken piece out, reattached the spring end and wound it back up in the housing. I am sure it lost a little pull, but the Oliver 9 still works well.You might want to see if you can pull the mainspring (which I assume is in some sort of housing) off and look inside. You may be able to reattach it (likely to a center spindle). Next best option would be to get a new mainspring/housing from a parts machine, but really, if you look at it, its not very complicated.
Regardless of the spring, yours certainly looks better than mine. Hope you fix it.
Can't beat it for $10. Sorry to hear of the problem, but a replacement mainspring should be easy to attain as soon as you find someone with a parts machine...and it seems like Bill is looking to help!
Congragulations! This one machine is a sort of "dream machine" of mine, hoping to get my hands on one soon!
I can imagine the fun getting the weight just right and the string to dangle the right way :-) Well done for persevering. I usually refer to the spring as the 'motor'. That's all it is, a clockwork driven, string powered motor. My biggest problem is that caps and figs on those older 3s are only accessible from the left keyboard and being a left hander, I can't type very well while holding down the shift. I usually end up typing with crossed hands. Especially like the up-and-downrhythm of the characters you are getting there - unique!