Hello Mel,
Chances are you do not have the stop motion tightened up enough, that is the chrome wheel in the middle of the balance wheel, what you can do is undo the small screw in the stop motion, undo the chrome stop motion wheel all the way off, you will see a three pronged washer, take the easher off and turn it round and put it in a different position then put everything back and try, when you put the stop motion wheel back on make sure you screw it up all the way but don't over tighten then tighten the small screw back up, if you can discribe your bobbin case to me whether you drop the bobbin straight in or if it goes into a seperate bobbin case, whether or not the machine has a reverse lever and the length of the base of the machine whether or not it is 12" or 14".
If you can e-mail a photo of the machine even better, any problems let me know, drivewithken@blueyonder.co.uk
Ken
drivewithken@blueyonder.co.uk, October 2007