MJ408E Electric Lawn Mower Sun Joe® MJ408E Electric Lawn Mower | Product Guide Mow with electric power and 3-in-1 lawn care convenience. The Sun Joe® MJ408E Electric Lawn Mower is designed for small to medium-sized residential lawns. It features a 12-amp motor, a durable 20-inch steel blade, 7-position manual cutting height adjustment, and three cutting options: bagging, mulching, and side discharge. It also includes a detachable 14.5-gallon grass collection bag, mulching plug, and side discharge chute. ⚡ No Gas or Oil🌱 7 Cutting Heights🧺 14.5-Gal Bag Meet the MJ408E Key Components 🖐️ Upper handle — main handle area for guiding the mower ⚙️ ON/OFF switch lever — starts and stops the mower motor 🔒 Safety lock button — must be pressed before pulling the switch lever 🔌 Appliance cord — connects to a properly rated outdoor extension cord 🧺 Grass collection bag — collects clippings for easy disposal 🌱 Mulching plug — recuts grass into finer clippings ↗️ Side discharge chute — directs clippings out the side when preferred 🎚️ Height adjustment lever — changes cutting height from 1.96 in. to 4.13 in. 🛞 Front and rear wheels — support smooth manual push operation 🧷 Cable clips — help keep the cord secured to the handle Technical Specifications Specification MJ408E Product Type Electric walk-behind lawn mower Best Use Small to medium-sized residential lawns Power Type Corded electric Rated Voltage 120V ~ 60Hz Motor 12 amps No Load Speed 3400 RPM Blade / Rotor 20 in. / 51 cm steel blade Cutting Width 20 in. / 51 cm Cutting Height Range 1.96 in. to 4.13 in. / 50 mm to 105 mm Height Adjustment 7-position manual height adjustment Cutting Options Bagging, mulching, and side discharge Grass Collection Bag Capacity 14.5 gal / 55 L Drive System Manual push Decibel Rating 96 dB Manual Net Weight 53.2 lbs / 24.2 kg Warranty 2 Year Warranty What's in the Box Included Item MJ408E Electric lawn mower ✔ Upper handle ✔ Lower handle ✔ Upper handle knobs and bolts ✔ 2 sets Lower handle knobs ✔ 2 knobs Grass collection bag ✔ Side discharge chute ✔ Mulching plug ✔ Manual and registration card ✔ Before You Mow 🚫 Safety first: Do not operate the mower in rain, damp grass, or wet grass. Keep hands and feet away from the blade and discharge openings. Always unplug the mower before assembly, cleaning, height adjustment, blade inspection, storage, or maintenance. ⚠️Inspect the mowing area before starting. Remove stones, sticks, wires, toys, and other debris that could be picked up and thrown by the rotating blade. Extension Cord Guide 🔌Use only an outdoor-rated extension cord. Use a UL-, CSA-, or ETL-rated cord suitable for outdoor, all-weather use. Do not use an extension cord longer than 100 ft. Extension Cord Length Minimum Wire Gauge Up to 50 ft / 15 m 14 AWG 50 ft to 100 ft / 15 m to 30 m 12 AWG Assembly 🚫Do not connect the mower to power until assembly is complete. Never operate the mower without the proper safety devices in place and working correctly. 1 Lower Handle Fit and tighten lower handle. › 2 Upper Handle Attach with knobs and bolts. › 3 Cord Clips Secure cord to handle. › 4 Cutting Mode Choose bag, mulch, or side discharge. Attach the lower handle Fit the lower handle onto the mower by inserting the threaded ends on the mower into the holes at the lower ends of the handle. Tighten the lower handle knobs. Attach the upper handle Align the upper handle with the holes on the lower handle. Insert the upper handle bolts from the inside and secure them with the upper handle knobs. Secure the cord Clip the cord into the cable clips on the handle to help keep it organized during operation. Bagging, Mulching + Side Discharge Mode How to Set It Up Bagging Lift the ejector flap and hook the grass collection bag rod ends into the small gaps near the wheels. Do not install the side discharge chute or mulching plug while using the bag. Side Discharge Lift the side discharge door, align the side discharge chute grooves with the pins under the door, and hook the chute into place. Do not install the grass bag or mulching plug while using side discharge. Mulching Lift the ejector flap, hold the mulching plug by its handle, tilt it about 15 degrees, and insert it into the rear discharge opening. Do not install the grass bag or side discharge chute while mulching. Cutting Height Guide 🚫Before adjusting cutting height: turn the mower off, unplug it, and wait until the blade has completely stopped. Wearing gloves is recommended due to the blade’s location. Position Cutting Height 1 1.96 in. / 50 mm 2 2.32 in. / 59 mm 3 2.68 in. / 68 mm 4 2.99 in. / 76 mm 5 3.35 in. / 85 mm 6 3.74 in. / 95 mm 7 4.13 in. / 105 mm Starting + Stopping Prepare the cord connection Push a loop of the extension cord through the extension cord restraint holder and around the restraint hook. Then connect the mower’s appliance cord to the extension cord. Place the cord safely Place the bulk of the extension cord on the lawn closest to the starting point. Keep the cord behind you and on the area already cut while mowing. Start on level, short grass Do not start the mower in tall grass. Hold the handle with both hands and tilt the handle downward slightly to raise the front of the mower before starting. Start the mower Press and hold the safety lock button, then pull the switch bar lever toward you. Once the motor starts, release the safety lock button. Begin mowing Let the motor come up to speed, then gently lower the mower into the cutting position and start mowing. Stop the mower Release the switch bar lever to stop the mower. ⚠️The blade continues rotating briefly after shutoff. Do not touch the blade area, remove the grass bag, or inspect the mower until the blade has fully stopped and the mower is unplugged. Mowing Tips 1 Mow dry grass only Do not mow in damp or wet conditions. Wet grass can reduce performance and increase electrical risk. 2 Use back-and-forth mowing paths Do not mow in circles. Travel back and forth across the lawn for a cleaner, more controlled cut. 3 Slow down in thick grass Reduce walking speed in thick grass to allow the mower to cut and discharge clippings properly. 4 Cut one-third or less For a healthy lawn, avoid removing more than one-third of the grass height in a single mowing session. 5 Use a higher setting for uneven ground Set the mower to the highest cutting height when mowing uneven ground or tall weeds. Maintenance & Care 🚫Always unplug the mower before cleaning, repairing, inspecting, changing accessories, or performing maintenance. Confirm all moving parts have stopped completely. 1 Clean after each mowing session Remove accumulated grass clippings and debris with a dry cloth or hand brush. A damp cloth may be used, but do not allow water to enter the mower. 2 Do not use running water Do not clean the mower with running water or high-pressure water. Water can damage the switch, plug mechanism, or electric motor. 3 Check hardware before use Check nuts, bolts, screws, wheels, handles, and guards before each use to make sure everything is secure. 4 Inspect the grass bag Frequently inspect the grass collection bag for wear or damage and replace it with a genuine replacement if needed. Blade Care ⚠️ The blade is sharp. Wrap the blade or wear heavy-duty gloves when handling it. Use extra caution and only use original replacement parts specified for this mower. Unplug and wait Disconnect the mower from power and wait until the blade has completely stopped. Secure the blade Turn the mower on its side and place a block of wood between the blade and mower deck to prevent the blade from turning. Remove blade hardware Use a 15 mm wrench or socket to loosen the blade nut, then remove the blade nut, washer, blade insulator, and blade. Install the replacement blade Use replacement blade MJ408E-BLD. Install the blade with the curved ends pointing up toward the mower deck, then reinstall the blade insulator, washer, and blade nut in the same order. Storage 1 Disconnect power Unplug the mower before preparing it for storage. 2 Clean the mower Use a damp cloth or hand brush to remove grass, dirt, and debris. 3 Inspect parts Check for worn, loose, or damaged parts. Pay special attention to the blade and replace or sharpen it if needed. 4 Store indoors Store the mower in a dry, clean, cool indoor area out of reach of children and away from corrosive materials like fertilizer or rock salt. 5 Do not cover with solid plastic Solid plastic coverings can trap moisture around the mower and may damage the unit. Troubleshooting Guide Use these quick checks for common MJ408E issues. Always unplug the mower before checking, cleaning, or maintaining the unit. 🔴 Motor Does Not Run Possible Causes Mower is unplugged or cord connection is loose Extension cord or outlet issue Circuit breaker or fuse issue Blade may be blocked Electrical brake may still be engaged after recent use Solutions Check the outlet, extension cord, and appliance cord connection Check the circuit breaker or fuse Unplug the mower and confirm the blade can rotate freely If recently used, let the motor cool before restarting Start on short grass or a previously mowed area 🟡 Motor Power Drops Possible Causes Cutting height is too low for grass conditions Extension cord is not the correct gauge or length Power source voltage is too low Air vents are blocked Solutions Raise the cutting height Use a suitable outdoor extension cord of proper gauge and length Use a proper power source Clean blocked air vents 🟡 Motor Performance Drops Possible Causes Cutting height needs adjustment Discharge channel or housing is clogged Blade is dull or damaged Solutions Correct the cutting height Clean the discharge channel and housing Replace or resharpen the mowing blade 🧺 Grass Bag Not Filling Well Possible Causes Grass is too wet Cutting height is not correct Grass bag grille is clogged Discharge channel or housing is clogged Solutions Allow the lawn to dry before mowing Correct the cutting height Clean the grille on the grass collection bag Clean the discharge channel and housing Optional Accessories Accessory Model 20-inch mower blade MJ408E-BLD 14.5-gallon grass collection bag MJ408E-BAG Side discharge chute for MJ408E MJ408E-39 Mulching plug for MJ408E MJ408E-MULCHPG Snow Joe® + Sun Joe® SJTW-A 14-gauge 50-foot extension cord with lighted end PJEXT50-B Video Guide Frequently Asked Questions What comes with the MJ408E? The MJ408E includes the electric lawn mower, upper handle, lower handle, upper handle knobs and bolts, lower handle knobs, grass collection bag, side discharge chute, mulching plug, manual, and registration card. Is the MJ408E gas-powered or electric? The MJ408E is a corded electric mower. It does not require gas, oil, pull-cords, or tune-ups. What size lawn is it best for? The MJ408E is best for small to medium-sized residential lawns. Can it mulch, bag, and side discharge? Yes. The MJ408E is a 3-in-1 lawn care tool with bagging, mulching, and side discharge options. Use only one cutting mode setup at a time. What extension cord should I use? Use an outdoor-rated extension cord. For up to 50 ft, use 14 AWG. For 50 ft to 100 ft, use 12 AWG. Do not use an extension cord longer than 100 ft. Can I mow wet grass? No. Do not use the mower in rain, damp grass, or wet grass. What are the cutting height options? The mower has 7 cutting height settings ranging from 1.96 in. to 4.13 in. Why should I start the mower on short grass? Starting in tall grass can strain the motor and make startup harder. Start on level, short grass or a previously mowed area, then move into the area to be cut. What replacement blade does it use? The replacement blade model is MJ408E-BLD. What warranty does it have? The MJ408E is backed by a 2-year limited warranty for ordinary household use when purchased from Snow Joe / Sun Joe or an authorized seller with proof of purchase. Related articles 24V-X2-PW1200 Cordless Portable Pressure Washer