Originally Posted by Deb watkins
My machine was doing that as well. I had to shut off the machine, give it a 10 second rest, rethread the top and also the bobbin...worked okay after that.
Make sure you presser foot is up when threading top thread. This will allow tension to grab hold. To test if top tension is alright put down presser foot and gently tug thread in needle. Thread should bend needle slightly if top thread is in tension mechanism correctly.