schuu6p,
If the main shaft is not turning then the stop motion nob is disengaged. It might feel tight, but it's not locking the hand wheel to the main shaft. That's it, there's nothing else there to be the problem.
Tighten the nob by turning it to the right or clockwise.
What I would do is get a small screw driver and loosen the little screw just far enough that you can remove the stop motion nob.
Then the clutch washer. Clean them then reinstall them. The washer goes on the main shaft with the two small prongs in the middle facing out towards the nob. It can go in two ways, so when you get the nob back on and the screw tightened, try it. It should rotate about a quarter turn or so then stop and at that point the hand wheel will free wheel. Turn it back to the right and it should tighten up. At that point the hand wheel should turn the main shaft.
If it doesn't, then remove the nob again, and rotate the clutch washer 180º. Reassemble it. It should work now.
Joe