The broken clutch spring would be the reason the clutch has been engaged all the time. The worn out clutch shoes may have happened by overloading the clutch, for example by running the engine with a toothed cutting blade stuck in a tree or whatever, or with a seized up gearbox at the bottom of the shaft.
You appear to need a new spring and a pair of new clutch shoes. These should all be standard service parts. It would seem that someone sold it to you because the clutch had been trashed by abuse.
When the clutch works properly it should be easier to start, since it won't have to turn the drive shaft when you pull the starter. However I'm not clear on how the carburetor would have been made without tuning adjustments for high and low speed mixture. It is possible, of course, that those adjustments would be covered and sealed for emissions control reasons.
