......... resurrecting an old thread ........
Bennett,
The tensioners are easy to remove and replace. One set screw and it's loose. The screw is on the under side of the head just to the right of the tensioner.
How they would work if interchanged I don't know. I have a 99K under repair and it's tensioner is available. I also have a couple 66s that I'd love to have the numbered tensioner on. I'm just leery of changing them out. It's taken a lot of tinkering to get these older machines to run with modern thread reliably so .......
Jacquie,
Sew-Classic has a selection of tensioner springs. I don't know which one your machine takes, but it might be work a look-see if you haven't found one yet.
Joe