JUKI MO600N Common Problems and Troubleshooting

Welcome to our guide on addressing common problems and troubleshooting for the JUKI MO600N sewing machine. As a proud owner of the JUKI MO600N model, you understand the importance of seamless sewing experiences. However, even the best machines can encounter issues. In this article, we’ll explore potential problems you might encounter with your JUKI MO600N and provide effective solutions to ensure your sewing projects continue without a hitch.

JUKI MO600N Overview

The JUKI MO600N is a versatile 2/3/4 thread serger equipped with automatic rolled hem capabilities. Its color-coded threading and breakaway looper, along with external adjustments for stitch length and differential feed, make it a user-friendly choice. The machine’s powerful knife system, supported by a dedicated drive mechanism, offers excellent sewing speed, with a maximum of 1500 stitches per minute. From light to heavy fabrics, the JUKI MO600N handles them all with ease.

Product Details

Product Dimensions 10.6″D x 13.6″W x 11.6″H
Item Weight 6.9 Kilograms
Power Source Treadle Powered
Is Electric Yes
Sewing Speed Max. 1500 spm
Max. Stitch Length 4mm
Safety Switch Machine will not run when swing cover is open
Differential Feed 0.7 : 2.0 Ratio
Included Components AccessoriesJUKI MO600N Series, MO654DE Portable Thread Serger Sewing Machine, White
Item Model Number MO-654DE
Customer Reviews 4.6 out of 5 stars

Causes of Common Problems with the JUKI MO600N

In the following sections, we’ll delve into the potential issues that you might encounter with your JUKI MO600N sewing machine and provide step-by-step troubleshooting solutions to keep your sewing experience smooth and enjoyable.

Common Problems and Troubleshooting for JUKI MO600N

1. Thread Tension Issues

Description: Uneven stitches or loops on the fabric, indicating thread tension problems.

Cause: Incorrect threading, improper tension settings, or lint buildup in the tension discs.


  1. Re-thread the machine following the correct threading sequence specified in the user manual.
  2. Check and adjust the thread tension settings for each thread as needed.
  3. Clean the tension discs and the surrounding area to remove any lint or debris.

2. Skipped Stitches

Description: Stitches are missing, creating gaps in the fabric.

Cause: Dull or bent needles, incorrect needle size for the fabric, or improper threading.


  1. Replace the needle with a new, appropriate-sized needle for the fabric you are using.
  2. Ensure the needle is properly inserted and tightened.
  3. Double-check the threading to make sure the thread is correctly passing through all guides and tension discs.

3. Fabric Doesn’t Feed Properly

Description: The fabric doesn’t move smoothly while sewing.

Cause: Incorrect differential feed settings, uneven fabric layers, or feed dog issues.


  1. Adjust the differential feed ratio to match the fabric type and thickness.
  2. Make sure the fabric layers are even and properly aligned before sewing.
  3. Check the feed dogs for any obstructions or damage and clean them if needed.

4. Rolled Hem Doesn’t Form Properly

Description: The rolled hem isn’t forming neatly, or the fabric is unraveling.

Cause: Incorrect settings for rolled hem, improper fabric handling, or blade alignment issues.


  1. Ensure you’ve selected the correct settings for rolled hem stitching.
  2. Practice folding and guiding the fabric for a clean rolled hem.
  3. Check the alignment of the cutting blade and make sure it’s sharp and properly engaged.

5. Machine Jams or Breaks Needles

Description: The machine gets stuck, or needles break during sewing.

Cause: Incorrect threading, fabric caught in the feed dogs, or bent/damaged needles.


  1. Stop the machine and unplug it if necessary to avoid further damage.
  2. Carefully remove the fabric from the machine and clear any threads or obstructions.
  3. Replace the needle with a new one and ensure it’s correctly inserted and aligned.

6. Uneven Stitch Length

Description: Stitches of varying lengths on the fabric, affecting the overall appearance.

Cause: Incorrect stitch length settings, worn-out feed dogs, or inconsistent fabric feeding.


  1. Adjust the stitch length settings to the desired value for your project.
  2. Inspect the feed dogs for wear and replace them if necessary.
  3. Ensure the fabric is being fed evenly and smoothly through the machine.

7. Thread Breakage

Description: Threads keep breaking during sewing, disrupting the stitching process.

Cause: Improper threading, incorrect thread tension, or burrs on the needle or thread guides.


  1. Re-thread the machine following the correct threading sequence.
  2. Check and adjust the thread tension for all threads according to the fabric being used.
  3. Inspect the needle and thread guides for any rough spots or burrs and smooth them out.

8. Noisy Operation

Description: Unusual noises or loud sounds coming from the sewing machine while in use.

Cause: Loose parts, debris in the machine, or lack of lubrication.


  1. Tighten any loose screws, bolts, or components in the machine.
  2. Clean the machine’s interior, removing any debris or lint that may be causing noise.
  3. Lubricate the moving parts of the machine as per the manufacturer’s guidelines.

9. Incorrect Rolled Hem Width

Description: The rolled hem is too narrow or too wide, not achieving the desired look.

Cause: Incorrect settings for rolled hem width, improper fabric handling, or blade alignment issues.


  1. Adjust the settings for rolled hem width to achieve the desired result.
  2. Practice folding and guiding the fabric to maintain consistent hem width.
  3. Check the alignment of the cutting blade and adjust if needed.

10. Tangled Threads on the Underside

Description: Threads getting tangled or bunched up on the underside of the fabric.

Cause: Incorrect threading, bobbin tension issues, or lint accumulation in the bobbin area.


  1. Check the bobbin threading and tension to ensure they are correctly set.
  2. Clean the bobbin area to remove any lint or thread fragments.
  3. Re-thread the machine, making sure the upper thread is correctly seated in all guides.

11. Breaking Needles

Description: Needles frequently breaking during sewing.

Cause: Incorrect needle type or size, hitting pins or zippers, or fabric jamming.


  1. Ensure you’re using the correct needle type and size for the fabric.
  2. Avoid sewing over pins or zippers, as they can damage the needle.
  3. Check for any fabric jams or obstructions in the sewing path.

12. Loopy Bobbin Thread

Description: Excessive loops or knots on the underside of the fabric.

Cause: Improper bobbin winding, incorrect threading, or bobbin tension issues.


  1. Ensure the bobbin is wound correctly, with even tension and the right thread.
  2. Re-thread the machine, making sure the upper thread is correctly seated in all guides.
  3. Adjust the bobbin tension to match the upper thread tension.

13. Fabric Puckering

Description: The fabric gathers or wrinkles while sewing.

Cause: Incorrect tension settings, wrong stitch type, or improper fabric handling.


  1. Check and adjust the tension settings for both upper and lower threads.
  2. Choose the appropriate stitch type for the fabric and desired result.
  3. Ensure smooth and even fabric feeding while sewing.

14. Stitches Skipping or Slipping

Description: Stitches appear uneven or shifted from their intended position.

Cause: Loose drive belts, timing issues, or incorrect machine settings.


  1. Check the drive belts for tension and tighten if necessary.
  2. Inspect the machine’s timing and make adjustments as per the user manual.
  3. Verify that the machine is set to the appropriate stitch type and settings.

15. Uneven Fabric Feed

Description: The fabric isn’t feeding evenly through the machine.

Cause: Dirty or damaged feed dogs, improper presser foot pressure, or incorrect settings.


  1. Clean the feed dogs and surrounding area to remove debris and improve traction.
  2. Adjust the presser foot pressure to match the fabric’s thickness.
  3. Ensure the machine is set to the appropriate stitch length and feed settings.

16. Uneven Gathering

Description: The fabric gathers unevenly while using the gathering stitch.

Cause: Incorrect tension settings, improper fabric handling, or uneven gathering ratio.


  1. Check and adjust the tension settings for both upper and lower threads.
  2. Ensure you’re guiding the fabric evenly while sewing to maintain consistent gathering.
  3. Review the gathering ratio settings and make necessary adjustments.

17. Bobbin Won’t Wind

Description: The bobbin isn’t winding thread properly during the winding process.

Cause: Incorrect bobbin placement, tangled thread, or a malfunctioning bobbin winder.


  1. Make sure the bobbin is correctly placed on the winder spindle.
  2. Check for any tangles or knots in the thread that might obstruct winding.
  3. If the issue persists, examine the bobbin winder mechanism for any defects.

18. Fabric Snags

Description: The fabric gets caught or snags while sewing.

Cause: Rough or damaged presser foot, burrs on the needle plate, or uneven fabric feeding.


  1. Inspect the presser foot for any rough edges or damage that might catch the fabric.
  2. Check the needle plate for any burrs or rough spots and smooth them out.
  3. Ensure the fabric is feeding smoothly and evenly through the machine.

19. Limited Stitch Variations

Description: The machine is not producing the expected variety of stitches.

Cause: Incorrect stitch selection, malfunctioning stitch selector, or software issues.


  1. Double-check the stitch selection to ensure you’ve chosen the correct stitch type.
  2. Test the stitch selector to see if it’s functioning properly or needs calibration.
  3. If the issue persists, consult the user manual for any troubleshooting steps related to software or settings.

20. Uneven Rolled Hem

Description: The rolled hem is uneven or wavy in appearance.

Cause: Incorrect fabric handling, inconsistent guiding, or blade alignment issues.


  1. Practice consistent fabric folding and guiding for a uniform rolled hem.
  2. Ensure you’re applying even pressure while guiding the fabric through the machine.
  3. Check the alignment of the cutting blade and adjust if necessary.

21. Excessive Thread Lint

Description: Accumulation of thread lint and debris in the machine.

Cause: Poor thread quality, lack of machine maintenance, or using low-quality thread.


  1. Use high-quality thread that is less likely to shed lint.
  2. Regularly clean the machine, removing lint and debris from the bobbin area and thread path.
  3. Consider using a thread net or guard to minimize lint buildup.

22. Inconsistent Serger Stitches

Description: Stitches from the serger are inconsistent in tension and appearance.

Cause: Improper threading, tension imbalance, or worn-out needles.


  1. Re-thread the serger following the correct threading sequence.
  2. Adjust the tension settings for both upper and lower loopers as needed.
  3. Replace worn-out needles with fresh ones suitable for the fabric.

23. Thread Popping Out of Needles

Description: The thread comes out of the needle during sewing.

Cause: Improper threading, incorrect needle installation, or thread tension issues.


  1. Re-thread the machine, making sure the thread is correctly seated in the needle’s threading path.
  2. Check that the needle is properly installed and tightened.
  3. Adjust the thread tension to prevent excessive pulling on the needle thread.

24. Stitching in Reverse Unintentionally

Description: The machine starts sewing in reverse without intended activation.

Cause: Sticky or malfunctioning reverse lever, foot pedal issues, or electronic glitches.


  1. Inspect the reverse lever for any obstructions or malfunctions.
  2. Check the foot pedal for any anomalies and ensure it’s functioning properly.
  3. If the problem persists, consult the user manual or seek professional assistance for potential electronic issues.

25. Poor Lighting

Description: Insufficient lighting around the sewing area.

Cause: Inadequate built-in lighting, dirty light bulb, or shadows cast by the machine.


  1. Consider using external lighting sources to illuminate your sewing area.
  2. If the machine has a light, clean the bulb or replace it with a new one if necessary.
  3. Adjust the position of your machine or the lighting to reduce shadows while sewing.

JUKI MO600N Sewing Machine User Reviews

Positive Reviews from JUKI MO600N Sewing Machine Users

  • Some users were satisfied with the ease of threading and setup of the JUKI MO600N sewing machine, finding the instructions and colored dots helpful.
  • Many users praised the machine’s performance, especially its stitching quality and speed.
  • Users appreciated the automatic rolled hem feature and its ease of use.
  • Several customers mentioned that the JUKI MO600N was an excellent upgrade from their previous sewing machines, providing better results and features.
  • Users noted that the machine’s stitch variety allowed them to tackle a wide range of sewing projects with ease.

Overall, the positive feedback suggests that many users found the JUKI MO600N sewing machine to be reliable, versatile, and a valuable addition to their sewing setup.

Negative User Reviews of the JUKI MO600N Sewing Machine

  • Some users experienced tension-related issues, including inconsistent stitching and looping, which impacted their sewing outcomes.
  • Several users reported difficulties in threading the machine, particularly with the needle, and expressed frustration with the threading process.
  • A number of customers mentioned receiving machines that had oil stains or leaks upon arrival, which required cleaning and raised concerns about the machine’s quality control.
  • Several users expressed disappointment with the machine’s durability, mentioning instances of the machine breaking down or malfunctioning within a relatively short period of use.
  • A few users encountered challenges in adjusting the tension properly, resulting in unsatisfactory stitch quality and frustration.

While some users faced issues with the JUKI MO600N sewing machine, it’s important to note that the negative feedback was relatively limited compared to the positive reviews.

5.0 out of 5 stars Best for home sewing. Reviewed in the United States on July 15, 2023 Verified Purchase

Got one for my wife. Better than singer/brother home-use sergers.

One person found this helpful

[Additional reviews]

JUKI MO600N Sewing Machine Manual

The operating instructions for the JUKI MO600N sewing machine can be found on the manufacturer’s official website. You can access the manual at the following link: JUKI Official Website.

JUKI MO600N Frequently Asked Questions

1. How do I thread the JUKI MO600N sewing machine?

Threading instructions are provided in the machine’s manual. Follow the step-by-step guide to ensure proper threading for optimal stitching results.

2. Why does my JUKI MO600N sew uneven stitches?

Uneven stitches can be caused by incorrect tension settings, improper threading, or fabric handling. Check and adjust the tension, rethread the machine, and ensure smooth fabric feeding.

3. How do I troubleshoot thread breakage issues?

Thread breakage can result from various factors, including needle issues, tension problems, or poor thread quality. Check and replace the needle, adjust tension, and use high-quality thread.

4. What should I do if the machine is not powering on?

Ensure that the power source is connected properly and the power switch is turned on. If the machine still doesn’t power on, check the power cord and consult the manual for troubleshooting steps.

5. How can I prevent fabric snags while sewing?

Fabric snags can occur due to a rough presser foot, burrs on the needle plate, or improper fabric handling. Smooth out any rough edges, ensure a clean needle plate, and guide the fabric evenly.

6. Why is my rolled hem uneven?

An uneven rolled hem can result from inconsistent fabric guiding or blade alignment issues. Practice even fabric folding and guiding, and check the alignment of the cutting blade.


Whenever you encounter a problem with your JUKI MO600N sewing machine, it’s recommended to refer to the manual provided by the manufacturer. Additionally, if you’re facing persistent issues, don’t hesitate to contact the customer service or service center for assistance. Proper maintenance, correct usage, and following troubleshooting guidelines can help ensure optimal performance and longevity of your machine.

JUKI HZL-G220 Common Problems

JUKI HZL-G120 Common Problems

JUKI MO644D Common Problems

Leave a Comment