First, be sure to have the presser foot in the RAISED position when threading the machine. When threading the tension disks, give each thread an extra little tug to make sure it is seated completely.

Start with brand new needles.

Be sure to thread the machine in the order recommended for the machine--most machines are 1) upper looper, 2) lower looper and the thread tail drapes over the upper looper, then 3) the needles. Pull all of the thread tails toward the back of the machine and under the presser foot.

Start out with the tension disks set at the midway point--this is the general tension for basic overlocking, but each machine is different and they may need to be tweaked to get them where they look best.

Perhaps you can find a manual.

New Home Sewing Machine Manuals PDF and CD

Make It Handmade Threading Your Serger or Overlocker

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjrmPaHhtnOAhVTHGMKHeY4BLcQFggeMAA&url=http%3A%2F%2Fjanome.com%2Fsiteassets%2Fsupport%2Fmanuals%2Fsergers%2Finst-book-7034d-english.pdf&usg=AFQjCNFntgvjSwJ-8qZxc6muEqF4gx_kAw&cad=rja

How to Thread Serger Overlock Machine

Janome Domestic Overlocking Machine Tutorial (this instruction threads the lower looper first!)

Note--be sure to clean and oil your machine frequently--probably every time a project is completed or more often as needed! Open the looper door and remove the lint & loose threads from inside the machine and then apply a drop or two of good quality sewing machine oil (or Tri-Flow Synthetic Lube) every place where metal rubs on metal. (Slowly rotate the handwheel and watch where things move.)

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