Serger User Guide

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Shop Area: Textiles

Tool: Juke Serger

Requires in-person training: No

Procedure Number

UG 140-03, Rev. 1





Juki Serger Model MO-654DE

Juki Serger.png

The JUKI MO654DE is a portable serger with 2-3-4 thread capability and automatic rolled hem stitching. It features adjustments for differential feed and stitch length to allow for maximum control while sewing.

Serger machines are basically upgraded versions of traditional sewing machines. This type of sewing machine is useful because of the different stitching it performs. Different to normal sewing machines, a serger will have fingers that are mechanical below the fabric, as well as needles above.


  • Keep fingers away from all moving parts. Special care is required around the serger machine needle and knife.
  • Always use the proper throat plate. The wrong plate can cause the needle to break.
  • Do not use bent needles.
  • Do not pull or push fabric while stitching. It may deflect the needle causing it to break.
  • Switch the serger machine off when making any adjustments in the needle area, such as threading needle, changing needle, threading looper, of changing presser foot.
  • Always unplug the serger from the electrical outlet when removing covers, when covers are opened to raise the knife or thread the loopers, when lubricating, of when making any other servicing adjustments.


JUKI MO-654DE/654 Instruction Manual (Page 2 of 40) | ManualsLib

mo-654_654de_instruction_manual_web.pdf (



2-3-4 Thread Capability with Automatic Rolled Hem The machine’s automatic roll hemmer rolls the edge of the fabric over itself two times in order to hide the edges of the fabric. The roll is sewn over while it is also rolled up. The automatic rolled hem feature offers two modes. The first allows for rolling over the end of the hem and the second allows for an overlock stitch for necessary durability. With either method the automatic hem provides a clean edge as needed for clothing and upholstery.

Differential Feed The differential feed is useful for stopping thin and stretchy materials from being pulled out of shape by seams. It changes the tightness of the material as it is stitched. An easy to use differential feed dial located on the exterior right hand side.

Adjustable Length and Differential Feed The serger features adjustment dials for the stitch length and the differential feed to provide the easiest management of each stitch. Change the stitch length for specialty thread or overlock techniques using the conveniently located dial.

Knife System The knife system uses a moveable upper knife for safety and simplicity with a dedicated drive mechanism. Knife adjustment is calibrated to offer consistent response. The knife system on the MO-654DE operates with a dedicated drive to assure consistent and easy cutting for both light and heavy weight fabrics.

Fabric Versatility Thanks to its differential feed the JUKI MO654DE can sew light or heavy fabric, even with thick seams. This is helped by the ability to place the presser foot in two positions by using the designated lever.

Built-in Tape Guide The presser foot features a built-in tape guide that can be used when sewing seams in stretchy fabrics. Using tape with these materials prevents the fabric from losing its shape during stitching while providing support to keep edges together.

Color-Coded Threading Guides Threading the MO-654DE is a breeze with color-coded and clearly marked thread paths.

Tension Adjustment 1-rotation thread tension dials with normal tensions highlighted for simple, consistent tension adjustment. Specially designed guides keep thread in place and ensure proper sewing tension at any speed.

Looper Threading The lower looper threader disengages for fast, easy looper threading, in seconds. Just slide the thread into the slot and snap the looper into place.

Multi-Function Presser Foot The multipurpose presser foot, standard on the MO-654DE, allows you to create overlock stitches and add tape, elastic, ribbon, or sequins. Snap-on presser feet to easily change from the multi-purpose foot to one of the Juki Specialty feet and expand the creative potential of the MO-654DE.

Serging Precision The built-in seam guide takes the guesswork out of seam allowances. Just use the conveniently located gauge on the guard cover and serge away, creating accurate seam allowances as you go.

Bright Lights Lighting on the MO-654DE provides optimum lighting to the fabric and needle areas.

Cutting Width Adjustment The lower knife cutting width easily and quickly adjusts with the turn of the dial allowing you to create perfect seams and rolled edges.


Juki Serger Detail List.png

Juki Serger Details.png

Juki Serger looper cover opened.png

Juki Serger Cloth plate opened.png


Handwheel (Pulley) – the handwheel turns towards you. Upon completion of threading, at sewing start end, be sure to turn the handwheel toward you.

Opening and Closing the looper cover Opening – to open the looper cover, pull the looper cover opening handle to the right and tilt the looper cover toward you, Closing – to close the looper cover, push up the looper cover, press if lightly to the right. The looper cover closes automatically.

'Opening and Closing the cloth plate Opening – press the cloth plate toward the outside. Closing – push the cloth plate toward the machine.

Juki Serger Presser foot lifter.png

Juki Serger Changing the presser foot.png

Juki Serger Releasing the upper knife.png

Juki Serger Lower knife adjusting knob.png

Juki Serger Differential Knob.png

Juki Serger Overlocking width selection knob.png

Juki Serger Presser foot pressure adjusting.png

Juki Serger Changing the needles.png


Juki Serger Threading prep and sequence.png

Juki Serger Threading the tension dials.png

Juki Serger Needle Threader.png

Juki Serger Upper looper thread Blue.png

Juki Serger Upper looper thread Blue Sketch.png

Juki Serger Lower looper thread Red.png

Juki Serger Lower looper thread Red Sketch.png

Juki Serger Right Hand needle thread Green.png

Juki Serger Right Hand needle thread Green Sketch.png

Juki Serger Left Hand thread needle Yellow.png

Juki Serger Left Hand thread needle Yellow Sketch.png

Juki Serger 4 mm wide 3 thread overlocking.png

Juki Serger 6 mm wide 3 thread overlocking.png

Juki Serger Adjusting the thread tension.png


Several common problems that occur in sergers:

Tension Troubles

  • Suddenly producing loose or poor stitches can be due to either improper tension settings or merely a threading problem. Check the tension settings and ensure they’re in the proper position for the fabric you’re using. If the top stitches are loose, increase the lower tension settings. Do the opposite if the lower stitches are loose.
  • If that doesn’t do the trick, try re-threading your serger and make sure the thread is seated properly on the tension disks. Run the thread(s) through the needles and slowly pull on the thread. If you feel any hesitation in the thread movement, check for snags on the spool pins and thread guides.

Skipped or Uneven Stitches

  • A bent, broken, loose or blunted needle is often the culprit when stitches skip. Check that both needles are securely seated and they exhibit no signs of dirt, oil or damage. If one or both look suspicious in any way, then securely insert new ones, making sure you’re using the right needle for the job. Needles can also become coated with residue from improperly prepared interfacing material.
  • If you do find a broken or damaged needle, it’s usually due to using the wrong type or size. Heavy woolens and often thick layers of denim, canvas or duck cloth require using a heavier, sharper needle. And remember, pulling the fabric while stitching can bend needles.
  • Poor stiches can also be due to the type and quality of the thread you’re using. Try not to purchase poorly spun bargain brands. When using 100% polyester thread, look for brands made in Europe. If planning to work with cotton-encased polyester, choose a good American brand.

Fabric Jams and Puckering

  • If the fabric you just started to stitch suddenly jams while traveling under the needles, it might be due to tangled thread caught in the feed dogs, stitch fingers or simply a loose or open looper cover. Check all three areas. If you do find caught or tangled threads, remove them and re-thread the machine. An improperly closed looper cover needs no special attention: simply secure it and try going on with your project.
  • Fabric puckers could be due to a few problems. They can include an overly long stitch length for the fabric type and weight, setting the presser foot pressure too high, using the wrong presser foot, working with the wrong type of thread or even a blunt needle. Also, make sure to back very sheer fabrics with tissue or removable backing.

Juki Serger Troubleshooting.png

                                             END OF THE PROCEDURE