1. Introduction
This manual provides detailed instructions for the safe and efficient operation, setup, maintenance, and troubleshooting of your Juki MO-6716 5-Thread Serger Overlock Sewing Machine. Please read this manual thoroughly before using the machine to ensure optimal performance and longevity.
2. Setup
2.1 Unpacking and Placement
Carefully remove the machine from its packaging. Place the machine on a stable, flat surface with adequate lighting. Ensure sufficient space around the machine for comfortable operation and fabric handling.
2.2 Power Connection
Connect the power cord to the machine's power outlet, typically located on the right side. Plug the other end into a suitable electrical outlet. The foot pedal also connects to a dedicated port on the machine. The power switch is usually located near the power cord connection point.
2.3 Threading the Machine
The Juki MO-6716 is a 5-thread serger, requiring careful threading for proper operation. The machine is designed to hold up to 5 spools of thread. Refer to the color-coded threading guides and the internal diagram located inside the front cover for precise threading paths. Each thread has a dedicated tension dial for adjustment.

Image: The Juki MO-6716 Serger, showing the multiple thread spools and tension dials on the front panel.
The internal threading diagram is a crucial guide for correct thread routing. Use tweezers or a threading tool to navigate threads through the intricate paths, especially for the loopers.
Threading Order (General Guideline):
- Upper Looper
- Lower Looper
- Right Needle
- Left Needle
Always ensure threads are seated correctly in their respective tension discs and guides to prevent skipped stitches or thread breakage.
3. Operating Instructions
3.1 Basic Sewing Operation
To begin sewing, lift the presser foot using the foot lift lever. Place your fabric under the presser foot, aligning the edge with the desired seam allowance guide. Lower the presser foot. Gently press the foot pedal to start sewing. The machine will automatically trim excess fabric as it stitches, creating a clean, finished edge.
3.2 Stitch Types and Adjustments
The Juki MO-6716 offers various stitch options, including 5-thread overlock with a chain stitch, and 3-thread overlock. These options allow for versatile garment construction and finishing. Adjustments for stitch length, differential feed, and cutting width are available via dedicated dials and levers on the machine. Experiment with different settings on scrap fabric to achieve the desired stitch quality for your project.
3.3 Tension Control
Each of the 5 threads has an individual tension dial. Proper tension is critical for balanced stitches. Adjust the tension dials according to the fabric type and desired stitch. Generally, a balanced stitch will have the needle threads meeting the looper threads at the fabric edge without pulling or looping. The internal threading diagram often includes recommended tension settings for common stitch types.
3.4 Fabric Handling and Seam Allowance
The machine features seam allowance guides on the needle plate to help maintain consistent seam widths. The built-in knife trims the fabric edge before the stitch is formed, ensuring a neat finish. For stretchy fabrics, the serger's stitch pattern provides durable yet flexible seams, ideal for knit garments.
4. Maintenance
4.1 Cleaning
Regular cleaning is essential for maintaining your serger's performance. Open the front cover to access the looper area and knives. Use a small brush to remove lint and thread scraps from around the feed dogs, loopers, and knife area. Periodically oil the moving parts as indicated in the machine's detailed manual.
4.2 Needle and Knife Care
The Juki MO-6716 is known for its sturdy needles and powerful knives, which contribute to its durability and cutting efficiency. Replace needles regularly, especially when working with different fabric types or if they become dull or bent. The knives are designed to be robust but should be inspected periodically for sharpness and replaced if they become dull to ensure clean cuts.
5. Troubleshooting
Most common issues with sergers are related to incorrect threading or tension settings. Always re-check your threading path and tension dials if you encounter problems such as skipped stitches, loose seams, or thread breakage. Ensure the machine is clean and free of lint buildup, which can interfere with thread movement and stitch formation. If mechanical issues arise, such as bent parts, consult a qualified technician.
6. Specifications
- Model: MO-6716
- Brand: JUKI
- ASIN: B0026SXBNW
- Thread Capability: 5-Thread
- Material: Metal
- Power Source: Corded Electric
- Electric: Yes
- First Available: April 18, 2009
7. Warranty and Support
For warranty information, technical support, or service inquiries, please refer to the official JUKI website or contact their customer service department. Keep your purchase receipt and model number handy for any support requests.





