This might help you to adjust the balance of your stitches:
NOTE YOUR CURRENT TENSION SETTINGS BEFORE MAKING CHANGES.
--Too little tension will give a loose stitch, causing thread loops in your seams. Adjust the thread tension to a tighter setting. (Your machine's thread tension may be a slider bar or a dial--move slider bar more to the "+" end (or) turn the dial to a higher number)
--Puckering seams may be from a tight stitch from too much tension. Try putting the tension to a looser setting (either more toward "-" (or) dial to a lower number.
--If you are still "looping" stitches, you might need to change your stitch length or put on a new needle. Also, the needle size may not be right for the type of fabric you are sewing.
Good luck--hope this is of some help.
Jennifer
February 2006