White Serger 1934D not stitching

You mean 'stitch length'? Width would be governed by the needles width

Manuals

Page 5 - Part 24 = Stitch Length Dial

https://www.manualsdir.com/manuals/719470/singer-wsl2000-ats-part-1-wsl2000-ats.html


https://www.google.com/search?q=white+superlock+2000+ats+manual+pdf

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First thing I would try is installing brand new needles. Also, has it been cleaned and oiled recently?

Serger Stitches 101 Cheat Sheet Never Ever Without It Your New Must Have...

Serger is Skipping Stitches Threads Magazine Gatherings Forum Sewing...

https://community.babycenter.com/post/a44997916/help_serger_skipping_stitches

SKIPPED SERGER STITCHES

Overlock Serger Troubleshooter

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SKIPPED STITCHES ON A SERGER

1. Is the needle bent or worn--replace

2. Is the needle inserted correctly into the needle holder--check needle

3. Is the Serger threaded correctly--rethread

4. Is the presser foot pressure right for the fabric--adjust
5. are the needles the correct ones for the serger
6. Possible timing problem--need to be checked at a sewing machine shop

SKIPPED STITCHES ON A SERGER
1. Is the needle bent or worn--replace
2. Is the needle inserted correctly into the needle holder--check needle
3. Is the Serger threaded correctly--rethread
4. Is the presser foot pressure right for the fabric--adjust

some times when you break a needle in a sewing machine or
serger it can cause the machine to jump time, it would be a good
idea to have the machine checked for a timing problem or to see
if when the needle broke it caused a problem with another part in
the serger.

Make sure you are threading the machine correctly. Make sure you are using serger thread that isn't old. Make sure you are undoing all the threads when it breaks and thread it from the beginning.

Make sure you have the right needles in their respective places. My Juki MO has two different size needles.

have you tried changing the needles?
if you have changed the needles & it's still skipping stitches the serger needs to be serviced

is it possible that the needles are in backwards?
it's very possible that the machine is out of time & would have to be taken to a sewing machine repair shop to be retimed

First, change the needles making sure to use the el705 needle system. Second, make sure the subsidiary looper is engaged properly (plugging up the upper looper hole). Also make sure the needles are all the way up in the machine. This should do it or it may need to be adjusted but the Evolve is a very, very reliable machine. Hope this helps...

Your machine cannot do a cover stitch. Check the Brother website, they make a cover stitch only machine, it works much better than any of the serger/cover stitch combination machines, and it is a lot less money.