I think this is a rebranded Tin Lizzie 18 LS. Look at the pictures from that company's site & compare it to your machine. I had a lot of issues with mine, however, tension wasn't one of them. I found this video very helpful:
https://www.youtube.com/watch?v=Q1mRhcquZTM
I couldn't keep the stitch regulator working, and finally just learned to quilt without it. Not as advertised, but certainly can be done, and I successfully did a lot of quilts that way until I upgraded to a different brand.
If I am correct, and it is a tin lizzie, there is a yahoo group dedicated to this machine and very helpful.