when I got my 301a a couple of yrs ago it also had tension problems. found that if I put the bobbin case from my FW in all was good. so for a long time I switched that bobbin back & forth between the two machines, then I finally invested in a new bobbin from NovaMontgomery.com who specializes in FWs. Do not buy the reproduction bobbin. that's what I had that did not work. I believe it cost $70, but decided I deserved the best! I really wanted to use that machine!
Good Luck, Jeanie in MO
PS. If you have a friend with a FW, you might see if you could try their bobbin in your 301. and find out if that fixes your problem
Last edited by Watson58; 03-14-2014 at 06:16 AM.