JUKI HZL-G120 Common Problems and Troubleshooting

Welcome to our guide on addressing common problems and troubleshooting for the JUKI HZL-G120 sewing machine. As proud owners of the JUKI HZL-G120 model, it’s essential to have a grasp of potential issues that might arise during its usage.

In this article, we’ll explore various common problems that users might encounter while working with the JUKI HZL-G120 sewing machine and provide effective solutions to tackle them.

JUKI HZL-G120 Overview

The JUKI HZL-G120 is a remarkable computerized sewing and quilting machine designed to deliver top-notch stitch quality and versatile functionality. Its box feed system ensures smooth fabric movement, eliminating any fabric shrinking or shifting.

The machine features an automatic needle threader for quick and hassle-free sewing startup. With 180 stitch patterns, 1 font, and drop feed capability for quilting, it’s a versatile companion for various sewing projects. Additionally, the machine offers powerful feeding, making it suitable even for heavy materials like denim jeans.

Product Details and Features

Item Weight19 Pounds
Power SourceCorded Electric
Is ElectricYes
  • Factory New Juki HZL-G120 Computerized Sewing and Quilting Machine
  • Perfect Stitch Quality: The box feed system moves the feed dog in a box motion, providing beautiful seams and outstanding feed performance.
  • Automatic Needle Threader: Thread the needle quickly with a simple lever push.
  • High-Quality Buttonholes: Create 8 different types of buttonholes with precision.
  • Drop the Feed Dogs and Go: Easily switch to free-motion quilting or embroidery.
  • Powerful Feeding: Improved presser foot construction allows sewing heavy materials with ease.

Note: This product is designed for use in the US. Check compatibility before purchasing for international use.

Product Description

Computerized sewing machine with 180 stitch patterns, 1 font, free arm, and hard cover. Features drop feed for quilting.

Product Information

  • Product Dimensions: 17.48 x 8.18 x 11.48 inches
  • Item Weight: 19 pounds
  • Manufacturer: JUKI
  • ASIN: B01B8HSB04
  • Country of Origin: China
  • Item Model Number: HZL-G120

Causes of Common Problems with the JUKI HZL-G120

Before we dive into specific troubleshooting tips, let’s take a moment to understand the potential causes of common issues that users might face when using the JUKI HZL-G120 sewing machine. The upcoming sections will provide detailed solutions to address these problems effectively.

Common Problems with the JUKI HZL-G120 and Troubleshooting

1. Thread Breakage During Sewing

Description: One common issue users might face is the frequent breakage of thread while sewing with the JUKI HZL-G120.

Cause: Thread breakage can occur due to incorrect threading, improper tension settings, or using low-quality thread.


  1. Re-thread the machine following the correct threading path as indicated in the user manual.
  2. Check the tension settings; ensure they are appropriate for the type of fabric you’re using.
  3. Use high-quality thread to reduce the likelihood of breakage.

2. Uneven Stitches or Skipped Stitches

Description: Stitches that are uneven in length or skipped stitches are common problems that can affect the sewing quality.

Cause: Uneven or skipped stitches can result from a dull needle, incorrect threading, or a damaged bobbin case.


  1. Replace the needle with a new one that’s appropriate for the fabric.
  2. Ensure the machine is threaded correctly, following the threading path in the user manual.
  3. Inspect the bobbin case for any damage; replace it if necessary.

3. Irregular Tension on Stitches

Description: Inconsistent tension on stitches can lead to unsightly loops or puckering of the fabric.

Cause: Incorrect tension settings, improper threading, or lint buildup in the tension discs can all contribute to this issue.


  1. Check and adjust the upper and lower tension settings according to the fabric you’re using.
  2. Ensure the machine is threaded correctly, and the thread is properly seated in the tension discs.
  3. Clean the tension discs and remove any lint or debris that might be affecting tension.

4. Noisy Operation

Description: Unusual noises during operation can be distracting and indicate a problem with the machine.

Cause: Noisy operation might be caused by a loose part, insufficient lubrication, or foreign objects in the machine.


  1. Tighten any loose screws or parts on the machine.
  2. Ensure the machine is properly lubricated as per the user manual recommendations.
  3. Inspect the machine’s interior for any foreign objects; remove them carefully.

5. Bobbin Winding Difficulties

Description: Users might encounter issues while winding the bobbin, affecting the availability of a stable bobbin thread.

Cause: Improper placement of the bobbin, incorrect bobbin winding setup, or tension problems can lead to difficulties in bobbin winding.


  1. Ensure the bobbin is placed correctly on the winding spindle.
  2. Follow the user manual instructions for proper bobbin winding setup.
  3. Check the tension disc for any debris or improper thread placement that might affect bobbin winding.

6. Bobbin Thread Tension Issues

Description: Uneven bobbin thread tension can lead to messy stitches and fabric puckering.

Cause: Incorrect bobbin threading, lint accumulation in the bobbin area, or bobbin case misalignment can cause tension problems.


  • Re-thread the bobbin following the proper path as per the user manual.
  • Clean out any lint or debris in the bobbin area regularly.
  • Ensure the bobbin case is properly aligned and securely inserted.

7. Fabric Not Feeding Properly

Description: Fabric not moving smoothly through the machine can lead to uneven stitching or fabric jams.

Cause: Incorrect presser foot pressure, feed dog issues, or using the wrong presser foot can hinder fabric feeding.


  • Adjust the presser foot pressure to match the fabric’s thickness.
  • Check for debris or thread tangles around the feed dogs; clean if necessary.
  • Ensure you’re using the appropriate presser foot for the type of stitching you’re doing.

8. Needle Breakage

Description: Frequent needle breakage can disrupt sewing projects and indicate underlying problems.

Cause: Using the wrong needle for the fabric, hitting pins, or needle misalignment can lead to needle breakage.


  • Choose the correct needle type and size for the fabric you’re working with.
  • Avoid sewing over pins to prevent needle damage.
  • Make sure the needle is properly inserted and aligned according to the user manual.

9. Thread Bunching on the Underside

Description: Thread bunching underneath the fabric can result in messy, tangled stitches.

Cause: Incorrect upper thread tension, improper threading, or bobbin-related issues can cause thread bunching on the underside.


  • Adjust the upper thread tension, ensuring it’s appropriate for the fabric.
  • Check the upper threading path and re-thread the machine if needed.
  • Inspect the bobbin for proper winding and correct placement.

10. Limited Stitch Options

Description: Users might find that certain stitch patterns or functions are not working as expected.

Cause: Incorrect mode selection, machine settings, or user error can limit stitch options.


  • Double-check that you’re in the correct mode for the desired stitch or function.
  • Review the machine settings and consult the user manual for guidance.
  • Ensure you’re following the correct procedure to access and activate different stitch options.

11. Thread Jamming in the Bobbin Area

Description: Thread getting jammed in the bobbin area can halt sewing progress and cause frustration.

Cause: Incorrect bobbin insertion, improper threading, or debris accumulation can lead to thread jamming.


  • Check that the bobbin is inserted correctly and rotates smoothly in its case.
  • Ensure the machine is threaded properly, with no loose threads or tangles.
  • Clean out any lint, threads, or debris from the bobbin area.

12. Inconsistent Buttonhole Quality

Description: Creating buttonholes that vary in size or quality can be a frustrating challenge.

Cause: Incorrect buttonhole settings, improper fabric stabilization, or a dull needle can affect buttonhole quality.


  • Review the buttonhole settings and adjust them according to your fabric and button size.
  • Stabilize the fabric with appropriate interfacing to prevent shifting during buttonhole creation.
  • Ensure you’re using a sharp needle suitable for the fabric type.

13. Thread Keeps Tangling or Knotting

Description: Constant tangling or knotting of thread can disrupt the sewing process and result in messy stitches.

Cause: Incorrect threading, upper thread tension issues, or using low-quality thread can cause tangling or knotting.


  • Re-thread the machine, following the correct threading path meticulously.
  • Adjust the upper thread tension to achieve balanced stitches.
  • Use high-quality thread that’s appropriate for the fabric.

14. Needle Won’t Move or Stuck

Description: The needle refusing to move or getting stuck in one position can indicate a mechanical issue.

Cause: Incorrect presser foot position, tangled thread in the shuttle, or a disengaged sewing mechanism can cause the needle to get stuck.


  • Check that the presser foot is lowered properly before sewing.
  • Inspect the shuttle area for any tangled thread; clear it if necessary.
  • Ensure the sewing mechanism is engaged and the machine is set to the correct mode.

15. Uneven Feed and Fabric Movement

Description: Uneven feeding or fabric movement can result in uneven stitches and a compromised final product.

Cause: Dirty or damaged feed dogs, improper presser foot pressure, or incorrect feed dog settings can cause uneven fabric movement.


  • Clean the feed dogs regularly to prevent lint buildup that affects fabric movement.
  • Adjust the presser foot pressure to match the fabric thickness.
  • Ensure the feed dog settings are appropriate for the sewing technique you’re using.

16. Needle Threader Not Functioning

Description: The automatic needle threader not working can slow down the sewing process.

Cause: Misalignment of the needle threader mechanism, bent needle, or improper use can lead to needle threader issues.


  • Check that the needle threader mechanism is aligned properly according to the user manual.
  • Replace the needle if it’s bent or damaged.
  • Follow the correct procedure for using the needle threader as outlined in the user manual.

17. Fabric Puckering

Description: Fabric puckering, where the material gathers or wrinkles while sewing, can affect the final look of the project.

Cause: Incorrect presser foot pressure, improper thread tension, or using the wrong needle can lead to fabric puckering.


  • Adjust the presser foot pressure to match the fabric and prevent excessive pressure on the fabric.
  • Check and adjust the upper thread tension to achieve balanced stitches.
  • Ensure you’re using the correct needle type and size for the fabric.

18. Thread Fraying or Breaking

Description: Threads fraying or breaking frequently can disrupt the sewing process and create unreliable stitches.

Cause: Using an old or incorrect needle, incorrect threading, or rough handling of the fabric can cause thread fraying or breakage.


  • Replace the needle with a new one suitable for the fabric type.
  • Double-check that the machine is threaded correctly and that the thread is seated properly in the tension discs.
  • Handle the fabric gently to avoid unnecessary stress on the thread.

19. Stuck or Unresponsive Controls

Description: Controls such as buttons, dials, or switches becoming stuck or unresponsive can hinder the sewing process.

Cause: Dirt, debris, or mechanical issues can lead to controls becoming stuck or unresponsive.


  • Check for any visible dirt or debris around the controls; clean them carefully if needed.
  • Refer to the user manual for maintenance instructions related to control mechanisms.
  • If the issue persists, consult a professional technician for further assistance.

20. Uneven Thread Tension in Zigzag Stitches

Description: Zigzag stitches with uneven tension can result in an irregular appearance.

Cause: Incorrect thread tension settings, improper needle positioning, or fabric manipulation can cause uneven tension in zigzag stitches.


  • Adjust the thread tension for zigzag stitches to achieve a balanced and even appearance.
  • Ensure the needle is positioned correctly; a misaligned needle can affect tension.
  • Practice smooth and consistent fabric manipulation while sewing zigzag stitches.

21. Thread Looping on the Bottom

Description: Threads forming loops on the underside of the fabric can lead to messy stitches.

Cause: Incorrect threading, upper thread tension issues, or bobbin-related problems can result in thread looping on the bottom.


  • Re-thread the machine following the proper threading path as specified in the user manual.
  • Adjust the upper thread tension to create balanced stitches.
  • Inspect the bobbin for correct winding and placement.

22. Skipped Decorative Stitches

Description: Decorative stitches not forming completely or being skipped can affect the final appearance of sewing projects.

Cause: Incorrect settings for decorative stitches, improper fabric handling, or dull needles can lead to skipped stitches.


  • Ensure you’re selecting the correct settings for the desired decorative stitch.
  • Practice steady fabric handling to prevent interruptions in the stitching process.
  • Use a sharp needle suitable for decorative stitches and the fabric type.

23. Bobbin Thread Showing on Top

Description: Bobbin thread appearing on the top side of the fabric can result in messy stitches and affect the final look.

Cause: Incorrect upper thread tension, improper threading, or bobbin-related issues can cause bobbin thread to show on the top.


  • Adjust the upper thread tension to achieve balanced stitches.
  • Re-thread the machine properly, ensuring the thread is seated correctly in the tension discs.
  • Inspect the bobbin for proper winding and placement.

24. Needle Up/Down Function Not Working

Description: The needle up/down function not responding as expected can impact sewing efficiency.

Cause: Mechanical issues, electronic glitches, or incorrect settings can lead to problems with the needle up/down function.


  • Check the settings and controls related to the needle up/down function; ensure they are correctly configured.
  • Power cycle the machine and test the function again; sometimes, a reset can resolve electronic glitches.
  • If the issue persists, consider consulting a professional technician for repairs.

25. Unwanted Fabric Movement During Stitching

Description: Fabric shifting or moving unexpectedly while sewing can lead to uneven stitches and inaccurate results.

Cause: Insufficient fabric stabilization, improper presser foot pressure, or incorrect handling can cause unwanted fabric movement.


  • Use appropriate stabilizers or interfacing to secure the fabric before sewing.
  • Adjust the presser foot pressure to match the fabric thickness and prevent shifting.
  • Practice consistent and gentle fabric handling to maintain control during stitching.

JUKI HZL-G120 Sewing Machine User Reviews

As part of our comprehensive review of the JUKI HZL-G120 sewing machine, we’ve gathered user feedback from various online sources to provide you with insights into the experiences of actual users.

Positive Reviews from JUKI HZL-G120 Sewing Machine Users

  • Many users were satisfied with the exceptional stitch quality achieved with the box feed system. They noted that this feature eliminated fabric shrinking and shifting, resulting in beautiful seams and precise feed performance.
  • Several users appreciated the automatic needle threader, mentioning how it made threading the needle effortless and allowed them to start sewing quickly.
  • Users found the machine’s high-quality buttonhole options to be a valuable feature, providing them with the ability to create beautiful buttonholes for a variety of projects.
  • Positive feedback was given to the drop feed feature, enabling users to engage in free-motion quilting and embroidery with ease, enhancing their creative possibilities.
  • Many users praised the machine’s powerful feeding capability, especially when working with heavy materials like denim jeans, expressing satisfaction with the results achieved.

Overall, the majority of users expressed high levels of satisfaction with the JUKI HZL-G120 sewing machine, highlighting its stitch quality, user-friendly features, and versatility in handling different types of projects.

Negative User Reviews of the JUKI HZL-G120 Sewing Machine

  • Some users experienced difficulties with tension-related issues, mentioning uneven stitches and thread looping as problems they encountered.
  • Several users reported challenges with thread tangling or breakage during sewing, impacting their sewing experience.
  • A few users expressed concerns about the automatic thread cutter not functioning as expected, leading to frustration during their sewing projects.
  • Some users found the machine’s controls to be unresponsive at times, affecting their overall sewing experience.
  • A small number of users mentioned difficulties with fabric movement and feeding, which impacted their ability to sew smoothly and achieve accurate stitches.

While there were some negative experiences reported, it’s important to note that these issues were not universally encountered and may vary based on individual usage and circumstances.

Overall, the majority of users were satisfied with the JUKI HZL-G120 sewing machine, praising its stitch quality, ease of use, and versatile features. These positive aspects seem to outweigh the reported negative experiences, making the JUKI HZL-G120 a popular choice among sewers.

JUKI HZL-G120 Sewing Machine Manual

The operating instructions for the JUKI HZL-G120 sewing machine can be accessed on the manufacturer’s official website. It’s important to refer to the manual for detailed guidance on setting up, using, and troubleshooting your machine. The manual provides valuable information to help you make the most of your sewing experience.

JUKI HZL-G120 Frequently Asked Questions

1. How do I thread the JUKI HZL-G120 sewing machine?

To thread the JUKI HZL-G120, follow the step-by-step threading guide provided in the user manual. The machine itself may also have threading guides illustrated on its body to assist you. Ensure that you thread the upper thread correctly through the tension discs and take-up lever, and that the bobbin is correctly wound and inserted.

2. Why does my machine keep jamming while sewing?

Jamming can occur due to various reasons, including improper threading, incorrect bobbin insertion, or debris in the bobbin area. First, re-thread both the upper thread and the bobbin thread, following the correct paths. Make sure the bobbin is inserted properly and that the area is clean and free from lint or stray threads.

3. How can I adjust the tension for different fabrics?

The tension settings can affect the quality of your stitches. Refer to the user manual to understand how to adjust the tension for various fabrics. Generally, you may need to experiment with the tension settings on a scrap piece of fabric to achieve balanced and even stitches. Keep in mind that different fabric types and thread weights may require different tension adjustments.

4. What should I do if the needle keeps breaking?

Needle breakage can result from factors such as using the wrong needle for the fabric, hitting pins, or a misaligned needle. Check that you are using the correct needle type and size for the fabric you’re sewing. Avoid sewing over pins and ensure that the needle is properly aligned and securely inserted according to the user manual.

5. How can I troubleshoot skipped stitches?

If you’re experiencing skipped stitches, it might be due to issues with tension, needle type, or fabric handling. Double-check your threading to ensure the upper thread is passing through all necessary guides and tension discs. Make sure you’re using the appropriate needle for the fabric, and try sewing at a slower and steadier pace to prevent skipped stitches.


For any issues or problems encountered while using your JUKI HZL-G120 sewing machine, it’s recommended to refer to the manual for specific guidance and troubleshooting steps. Additionally, if you’re unable to resolve the issue on your own, don’t hesitate to reach out to JUKI’s customer service or a professional service center for assistance. Proper maintenance and care, along with following the manufacturer’s instructions, will ensure that you get the most out of your sewing experience with the JUKI HZL-G120.

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