Sun Joe MJ401E-PRO
Sun Joe MJ401E-PRO 14-Inch 13-Amp Electric Lawn Mower Instruction Manual
Model: MJ401E-PRO | Brand: Sun Joe
1. Introduction
This manual provides essential information for the safe and efficient operation, assembly, and maintenance of your Sun Joe MJ401E-PRO Electric Lawn Mower. Please read all instructions carefully before use and retain this manual for future reference.
Key Features:
- Powerful 13-Amp Motor: Delivers efficient cutting performance for a 14-inch wide path.
- Adjustable Cutting Height: Features a 3-position manual height control to tailor cutting height from 1.18 inches to 2.52 inches.
- Durable Steel Blade: Equipped with a 14-inch steel blade for precise cutting.
- Grass Collection System: Includes a 10.6-gallon hard top rear collection bag for convenient grass disposal.
- Side Discharge Chute: Comes with a side-discharge chute (MJ401E-DCA) for cutting taller grass without clogging.
- Collapsible Handle: Designed for compact storage.
2. Product Overview
Familiarize yourself with the components of your Sun Joe MJ401E-PRO Electric Lawn Mower.

Figure 2.1: Overall view of the Sun Joe MJ401E-PRO Electric Lawn Mower.
Included Components:
- Electric lawn mower unit
- Grass bag
- Grass bag support rod
- Side-discharge chute
- Upper handle
- Upper handle knob and bolt assembly (2)
- Lower handle
- Lower handle screws (2)
- Extension cord restraint hook
- Cable clip (2)
- Spanner
- Manual and registration card
3. Setup and Assembly
Follow these steps to assemble your electric lawn mower. For a visual guide, refer to the assembly video below.
Video 3.1: Quick assembly guide for the Sun Joe MJ401E-PRO Electric Lawn Mower.
Assembly Steps:
- Attach Lower Handle: Align the holes on the lower handle with the corresponding holes on the machine body. Secure the handle on both sides using the provided screws.
- Install Extension Cord Restraint: Slide the extension cord restraint holder onto the upper handle.
- Connect Upper Handle: Align the holes on the upper handle with the lower handle assembly. Fit a washer to the outside of the handle, insert the bolt through the holes, and attach the knob. Twist until tight. Repeat for the other side.
- Assemble Grass Bag: Fit the grass bag support rod into the plastic cover of the grass bag.
- Attach Grass Bag: Lift the ejector flap at the rear of the mower and attach the assembled grass bag by fastening it onto the coupling hooks.
- Attach Side Discharge Chute (Optional): To attach the side discharge chute, slide the chute tabs onto the coupling hooks located on the side of the mower.
- Secure Cables: Use the provided cable clips (x2) to secure the power cable along the handle for safe operation.
4. Operating Instructions
Proper operation ensures effective lawn care and user safety.

Figure 4.1: Operating the lawn mower on a lawn.
Starting the Mower:
- Ensure the mower is on a level surface and clear of debris.
- Connect the extension cord to the mower's power inlet and secure it with the restraint hook.
- Press and hold the safety switch button, then pull the instant start lever towards the handle. The motor will start.
- Release the safety switch button, but continue to hold the instant start lever to keep the mower running.
Adjusting Cutting Height:
The mower features a 3-position manual height adjustment. To change the cutting height:
- Turn off the mower and disconnect it from the power source.
- Carefully tilt the mower on its side.
- Adjust all four wheels to the desired height setting (1.18, 1.85, or 2.52 inches) by repositioning them in the appropriate slots.
Grass Collection and Discharge:
The mower can be used with the grass collection bag or the side discharge chute.

Figure 4.2: Detaching the grass collection bag.
- For collecting clippings, ensure the grass bag is securely attached. Empty the bag when it is full to maintain optimal performance.
- For side discharge, remove the grass bag and attach the side discharge chute. This is ideal for taller grass where collecting clippings is not desired.
5. Maintenance
Regular maintenance ensures the longevity and safe operation of your lawn mower.

Figure 5.1: Underside of the mower with the blade.
General Cleaning:
- Always disconnect the power cord before cleaning or performing any maintenance.
- Clean the exterior of the mower with a damp cloth. Do not use harsh detergents or solvents.
- Remove grass clippings from the underside of the mower deck and around the blade after each use to prevent buildup and ensure efficient cutting.
Blade Care:
- Inspect the blade regularly for sharpness and damage. A dull or damaged blade can affect cutting performance and may require sharpening or replacement.
- When handling the blade, always wear heavy-duty gloves to prevent injury.
6. Troubleshooting
Refer to this section for solutions to common issues you might encounter.
| Problem | Possible Cause | Solution |
|---|---|---|
| Mower does not start | No power supply; Safety switch not engaged; Loose connections. | Check power outlet and extension cord; Ensure safety switch and lever are correctly engaged; Verify all connections are secure. |
| Poor cutting performance | Dull or damaged blade; Cutting height too low for grass type; Grass clippings clogging the deck. | Sharpen or replace blade; Adjust cutting height; Clean underside of mower deck. |
| Excessive vibration | Bent or unbalanced blade; Loose components. | Inspect blade for damage and replace if necessary; Check all fasteners for tightness. |
7. Specifications
Detailed technical specifications for the Sun Joe MJ401E-PRO Electric Lawn Mower.
| Feature | Specification |
|---|---|
| Brand | Sun Joe |
| Model Number | MJ401E-PRO |
| Power Source | Corded Electric |
| Motor | 13-Amp |
| Cutting Width | 14 Inches |
| Cutting Height Positions | 3 (1.18" to 2.52") |
| Grass Bag Capacity | 10.6 Gallons |
| Blade Material | Stainless Steel |
| Item Weight | 30 Pounds |
| Product Dimensions | 48.4"D x 40.6"W x 40.6"H |
| No Load Speed | 3500 rpm |
| UPC | 787392915494, 810829024442 |
8. Warranty and Support
Your Sun Joe MJ401E-PRO Electric Lawn Mower comes with a 2-year manufacturer's warranty.
For technical support, warranty claims, or to purchase replacement parts, please visit the official Sun Joe website or contact their customer service department. Refer to the product packaging or the Sun Joe website for the most current contact information.
Ask a question about this manual
Ask about setup, troubleshooting, compatibility, parts, safety, or missing instructions. Manuals+ will review the question and use this page’s manual context to help answer it.