Thank you all so much for your input. Indeed it appears that a non-original bobbin case is to blame for my currently unusable FW. I have looked for parts online and will order a proper bobbin case shortly. Can't wait for it to be delivered! In the meantime I will thoroughly clean my machine as it appears to be quite dirty -- it smells eww and the thread comes up rusty from traveling through the thread guides. I have looked through the forums for hints regarding such a cleaning process. This is such a helpful place, I am so glad to have found it!
For those wondering where the pics are: here's the link, hopefully it works:
http://www.quiltingboard.com/members...bums13593.html