I changed a Bernina2000DCE from serging to coverstitch. Changed plate, changed foot, blade up and clicked into the upright position. However when I put the replacement cover on to protect the lower looper, the upper looper that is not being used is hitting the top and making a noise. Can I fix that? It is making great stitches so I am not worried about that but I was doing it for someone else and they are nervous about it. I know its not quite right. Thanks, Shirley

Sewing Machines - Bernina