1) Incorrect Needle – Try a larger Needle. Needles are available in sizes from #000 to #8. The larger the number the bigger the Needle.
 
2) Needle Carrier Stud is Loose – The Needle Carrier Assembly must be free to swing upon the Stud, but must not have any right to left lateral movement.

To adjust the Stud loosen the set screw, 4 9/32. Tighten the Needle Carrier Stud until it stops, then back it out 1/12 of a turn (30 degrees).

3) Check the Looper Setting – Check that the Needle is not impacting or bending when it passes the Loopers.
 
4) Needle Carrier Stud Hole is Worn – If a customer finds that he or she is continually readjusting the Needle Carrier Stud, it is a good indication that the Needle Carrier Stud hole is worn out. The machine should be shipped to the Merrow factory for service.