I have a Nelco Sierra sewing machine that is jamming up in the bobbin area and won't sew. It just knots up. Why? How do I fix this problem?
Take the needle plate out. Make sure there is not dust, lint, thread or fabric jams in the area.
You'll need to remove the bobbin from the machine.
Then remove the needle plate.
Clean this area completely and remove all the dust and pieces of thread.
Add a bit of oil, not too much.
Now put it back together.
same thing on mine....someone said buy a thick strong needle