2000ats - not serging

Pull more thread tail through the needles before beginning to serge. Also, if you stitch off the fabric when at the end and then clip through the locked stitches, you probably won't have the threads pulling backwards.

Check to be sure you are using needles and thread that are compatible with the fabric. Generally, finer threads will work better on fine fabrics along with a smaller needle. Be sure to change needles frequently as dull, bent, or nicked needles will cause very frustrating issues.
All About Needles

Remove the thread completely from the machine. RAISE the presser foot and rethread from the beginning, making sure the thread path is correct.

Some machines have a presser foot pressure adjustment (consult the owner's manual). Adjusting the pressure that the presser foot applies to the fabric & feed dogs is helpful when sewing especially fine or heavy fabric. Also, when sewing fine fabrics, loosening the tension could be beneficial.

Changing presser feet may also help, ie try using a straight stitch foot vs a presser foot for zig-zag stitching.

Something else you can try is finding a presser foot with a teflon finish or a roller foot that will glide or roll with the fabric through the machine. Even if you can't find a brand name presser foot for your particular machine, an adapter shank can probably be found that would allow you to use snap-on feet of all different designs and uses. Provides a lot of choices for presser feet for less than purchasing a brand-name presser foot. There are snap-on kits available on eBay and other auction sites.

Some machines also can take a straight-stitch needle plate--usually an additional accessory that can be purchased. The hole where the needle penetrates the needle plate to access the bobbin thread is actually a small round hole. With a zig-zag needle plate, the hole the needle penetrates is a wide rectangular hole that can allow fine fabrics to be pulled down through the hole. Zig-zag capable machines usually have a zig-zag needle plate as standard.

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Timing an overlocker is NOT for home service, it takes training, tools, gauges and experience take it in to get it fixed

From "Serge With Confidence" by Nancy Zieman:

Set the machine up for a 3-thread rolled edge. Normal width; length 1 - 2.

Use Woolly Nylon in the loopers & regular thread in the needle.

Lock or disengage the cutting blade.

Guide fabric along the right edge of the presser foot.

Stretch and equal amount from fron to back while serging.

Lower the differential feed, if available to about 0.6.

Serge at a slow to moderate speed.

Practice with scraps first.

After serging, gently stretch & release the fabric edge after serging.

If you mean the threads get tangled behind the presser foot then maybe this can help. Try pulling the threads gently as you guide the fabric through the first time. Also, I sometimes put a scrap piece of fabric under the presser foot with the edge lined up with the needles (so it is further back than normal). Then I gently press the speed control foot and pull on the threads. This allows the needles to start sewing right away on the fabric rather than giving the thread a chance to get tangled. Hope that helps!

Hello,
Try these solutions.

* Re-thread your needle
It may be threaded incorrectly (backwards).

* Reinsert your needle
Make sure it goes all the way into the holder and that it’s positioned correctly – usually with the
flat side away from the bobbin, but consult your machine’s manual to be sure.

*Change your needle
Your needle may be blunt, bent, or otherwise damaged.

*Your fabric may require a different needle. Generally, heavier fabrics require larger needles and
thinner fabrics, smaller needles. You may also need a larger needle if
you’re sewing through many layers of fabric. And make sure to use a ballpoint needle for knit fabrics and a sharp needle for wovens (or a universal needle for either).
And make sure your needle is appropriate for the type of thread you’re using.

* Adjust the pressure of your pressure foot
It may be too light for your fabric.

* Change your thread
If your upper thread and bobbin threads are different types, try using the same thread for
both. And use a good quality, brand name thread.

* Adjust your thread tension
It may be too tight or too loose.

* Re-thread your machine
It may be threaded incorrectly.

* Change your needle plate
Try switching to a needle plate with a smaller hole (a straight stitch needle plate).

Important: If you change your needle plate, check to make sure your needle aligns perfectly with
this smaller hole before starting to sew. A misaligned needle could hit the plate and break, which
could be dangerous. And make sure to change your needle plate back for zigzag and other wide
stitches.
I hope this helps you.

The loopers must be threaded before the needles.

Make sure that the needles are not threaded. Thread the loopers and have the loose ends behind the presser foot. Then re-thread the needles and place a scrap of fabric under the foot and sew. Make sure that the edge of the fabric is not to the right of the plate, but where it would be if the knife had cut it.

Check that your lower looper is actually threaded and not tangled with the upper looper (needle thread) when it moves. I wish they'd include pictures in the manual how to lay the thread.

• the factory default settings are 4,4,4,4 and M
• Change the needles
• use a can of air spray ( compressed air can sold in computer stores) to ensure there is no fabric or dust under the needle plate

change the knife blades