Originally Posted by Tallulah
I was having a fit with my FW bunching up the bobbin thread the other night. Finally, I decided to rethread it. Started working like a dream. I don't know why it took me so long to remember to try this, because it is a good go-to before pulling your hair out. May not always be the answer, but several times on various machines, it has corrected my problem.
Great observation. Re-threading the top and placing the thread correctly between the tension discs usually solves the problem for me, too.