Report "Speedylock differential 1600 serger. I brought serger in to service to repair 3 times. each time it worked for about 3 minutes and seemed to break. I opened the bottom and found a screw out. It seemed to go in to the upper looper mechanism. I screwd it back in and now the mechanism goes back up and down but it seems the timing is off. I want to fix myself but not sure how to do that"