Sergers are powerful tools that can speed up almost any sewing project, but traditional sergers often go out of time. Notice there are two loopers one that moves under the needle plate and one that goes over the top. If you understand oscillating hooks, apply the same principles here. It should take no more that a couple of minutes to properly set the timing. Just remember, the lower looper moves clock wise and the upper looper moves counter clock wise. Each looper has an eye and a scarf just like needles. Make sure your sergers are moving properly in time.