We may have found other answers which could help you.
Click here for Sewing Machine Thread Tension
Frister Rossman cub 7 - timing?
Frister Rossman 300 cog broken?
Frister Rossman cub 3 - How to take it apart?
Tension wont move on Frister Rossman 972?
new motor for Frister rossman cub 4 where can I buy?
New part for Frister Rossman Panda 6 mark 2 sewing machine?