FMQ on Featherweight
i just bought an original f/w with the booklet included. Upon reading the info about quilting, I discovered that when you thread the machine - after you thread the tension disc and go to the lever just to the left of the tension disc, make sure the thread is in the HOLE of that lever (lower one). I haven't tried it, but this info comes from the book. I looked at my other f/w and saw that the thread was in the hole - then I realized that's why I couldn't adjust the stitching when I sat down to sew on it.
Try this and see if it works on some scrap material.
good luck
alisa