There is a bobbin in the case. The thread moved freely when I pulled on it so I pulled out all of the thread. Doesn't appear to be any more thread in there. I think the bobbin is causing the problem so I'll have to remove the race mechanism. How do I do this? This is a link to the manual but it has nothing about removing the race mechanism.
http://www.singerco.com/uploads/down...ff8e037f58.pdf