She said there was nothing wrong with it, it just needed cleaning and oiling. The machine looks very well cared for and little used but it had a very loud clanking sound when operated. Except for that noise, the machine ran smoothly and, with the bobbin case /shuttle removed, very quietly so I was pretty certain where the noise was originating from. I opened up all the panels and oiled everything and, while doing that, found some thread wrapped around the knuckle of the thread take-up lever.
Here's where it gets goofy - AFTER I removed the thread, the machine locked up so tight that the motor wouldn't turn it over and it was difficult to rotate by hand! I looked for additional thread clogs and re-oiled evrything with no improvement. To isolate, I disconnected the connecting rod that transmits movement from the main shaft to the lower section.
This cuts the mechanism in half and tells me whether the problem is in the upper or lower section. It was in the upper section. Having exhausted all my ideas, I doused the whole upper section with Liquid Wrench and let it sit overnight. This morning, it seemed a bit looser turning by hand and, after a few revolutions, the motor took over and spun the shaft. I ran in the machine at top speed for about a minute and all the binding is gone. I have no idea where the problem was.
Then on to the noise in the shuttle area. The thread gap between the tip of the shuttle cushion spring and the shuttle should be just over the thickness of thread but this one was a good 1/8 inch.
I rummaged through all my parts bins and could not find a single cushion spring. Apparently, that is something that needs replacing so seldom that I haven't kept any spares. Then I remembered the Julia I am parting out still has the cushion spring so I cannibalized it but it is too long to work in the Kenmore. Fortunately, my parts source has the springs and attaching screws in stock, so I can order replacements.
Ed's Vintage Sewing Machine Shop