While you wait for answers, we may have found some information which could help you.
Click here for Tension Very LooseHow to switch on light of sewing machine?
Frister & Rossmann cub 7?
Sew-tric ltd variable speed motor built 1982 6000rpm r007327?
Presser foot level, needle and thread guide have fallen out?
Toyota SL3404D Overlocker leaving big loops?
Singer zigzag 457 Stylist not threading bobbin/making stitch?