Thanks so much, sunflowerzz! I am going to try getting that knee pedal together, now.
As for the tensioner ....I actually took the faceplate off the machine so that I could take the tensioner apart for cleaning. I took pictures of what it looks like and will post them here tomorrow. It was still sort of tight but I think I have found the problem.
I have a manual that I printed out. I think I got it from the files of the Vintage Elna yahoo group but thanks for your offer!