Fixing the tensions. Bottom thread is too loose.
Although a bobbin tension adjustment may be needed it is more likely the issue you are having is related to a failure of top thread feed or tension.
To test top thread feed and tension, place presser foot up and needle up. Select a tension setting of approximately four (4). Make a long slow steady pull of top thread. The thread should advance easily through the needle eye with out hesitation or snagging. This is "no tension" of top thread as foot is up. Any snagging would imply uneven feed from top spool or miss-threading.
Now place foot down and make another long slow steady pull of top thread. Note the difference in no tension (foot up) and selected tension (foot down). Again the thread should advance through the eye of the needle without snagging or abrupt change in tension.
If you find no problem with top thread tension then you can do a test of bobbin tension. With needle up and foot up, make a long slow steady pull of bottom thread. It should advance smoothly from the bobbin (case) without snagging or abrupt change in tension. It should have a similar tension to top thread foot down.
Comment below with your results so I may assist further if need be.
×