I assume that the bobbin race is spotless. The Elna has very tight specs and even a tiny bit of thread will cause the problems you mentioned. You have to hold both threads to start - same result. I don't know which model you have, but he 62C needle threads front to back. Sometimes it's the little things and Miss Elna is a very particular machine, but the most perfect stitching one I have ever sewn on. Mine isn't fussy about bobbins, strangely enough.