It definitely looks like a tension problem to me. I just don't want to get used to the computerized machines. Just give me my old featherweight or my treadle. The stitch is so straight and even. I have an old Singer 128 portable that was in storage for over 25 years. It is 80 years old. We cleaned it up, oiled it, I sat down to sew with it and it put out the prettiest stitch without any problems. Just call me an old timer.