Yes, we tried adjusting the tension but to no avail. Thank you everyone for your helpful insights which we will be trying. Thanks again!

I posted at 9am that tension is only an issue if your tension is off with straight stitching. What size needle and thread weight are you using? Recommended needle size is 90/14. Depending in thread weight you may need a Microtex needle...90/14, or a 90/14 topstitch needle. Let us know.