MJ401C 28-Volt Cordless Lawn Mower Sun Joe® MJ401C Cordless Lawn Mower | Product Guide Cut the cord and mow with cordless convenience. The Sun Joe® MJ401C Cordless Lawn Mower is designed for small lawns and residential grass cutting. It features a 28V 4.0 Ah lithium-ion battery, 600 W brushless motor, 14-inch cutting width, 3-position cutting height. 🔋 28V Cordless Power🌱 Small Lawn Ready🧺 10.6 gal Grass Bag Meet the MJ401C Key Components ▶️ Switch lever — squeeze to run the mower after pressing the safety lock button 🔒 Safety lock button — helps prevent accidental starting 🔑 Safety key — must be inserted before operation and removed before maintenance 🔋 Battery capacity indicator — shows remaining battery charge under the gauge cover 🔌 Charge socket — connects the included iCHRG28-AC charger 🛞 4 wheels — each wheel axle adjusts to low, medium, or high cutting height ✂️ Steel blade — 14-inch cutting path for residential mowing 🧺 Grass collection bag — 10.6 gal / 40 L clipping collection capacity 🚪 Ejector flap — helps secure the grass collection bag during use 🧰 Handle knobs + bolts — secure upper and lower handle assembly 📎 Cable clips — keep the control cable secured to the handle 🔌 iCHRG28-AC charger — charges the mower battery in up to 4.5 hours Technical Specifications Specification MJ401C Product Type Cordless walk-behind lawn mower Best Use Private residential grass cutting in small lawns and gardens Motor 600 W brushless Battery Voltage Max 28V D.C.; initial no-load voltage peaks at 29.4V when fully charged Battery Capacity 4.0 Ah Charger Model iCHRG28-AC Charger Input 100–240V AC, 50–60 Hz, 0.8A Charger Output 29V DC, 0.9A Battery Charge Time Max 4.5 hours No Load Speed 3000 rpm Cutting Width Max 14 in. / 35.6 cm Cutting Height 1.2 in. to 2.5 in. / 30 mm to 64 mm Height Positions 3 positions: low, medium, high Grass Bag Capacity 10.6 gal / 40 L Blade Material Steel Wheel Size 5.5 in. / 14 cm Net Weight 23.1 lbs / 10.5 kg Warranty 2 Year Warranty What's in the Box Included Item MJ401C Cordless lawn mower ✔ Grass collection bag ✔ Grass collection bag support rod ✔ Upper handle ✔ Upper handle knob and bolt assembly ✔ 2 included Lower handle ✔ Lower handle screws ✔ 2 included Screws ✔ 2 included Cable clips ✔ 2 included Battery charger ✔ Manual ✔ Before You Mow 🚫Keep hands and feet away from the mower blade and discharge opening. The blade can continue rotating briefly after the mower is switched off. Wait until the blade fully stops before touching, lifting, cleaning, or inspecting the mower. ⚠️Remove the safety key before maintenance. Always turn the mower off and remove the safety key before assembly, cleaning, blade checks, charging setup, storage, or any adjustment. 👟Use safe mowing habits. Wear eye protection, hearing protection, gloves, and non-slip footwear. Clear the lawn of stones, sticks, wires, toys, and other objects before mowing. 🌧️Do not mow in rain or wet grass. Keep the mower dry and use it only in daylight or good artificial light. Assembly 🚫Do not insert the safety key until assembly is complete. The mower must be fully assembled before operation. 1 Lower Handle Attach to mower body. › 2 Upper Handle Secure with knobs and bolts. › 3 Grass Bag Install support rod. › 4 Fit Bag Hook under ejector flap. Attach the lower handle Fit the lower handle into the two holes in the mower body and fasten both sides with the provided screws. Attach the upper handle Join the upper handle to the lower handle using the knob, plastic washer, and bolt. Repeat on the opposite side. Assemble the grass collection bag Fit the support rod into the holes in the plastic cover. The bend of the support rod should face the rear of the mower. Install the grass collection bag Lift the ejector flap with one hand, hold the grass bag by the handle, hook it in from above, then release the ejector flap to secure the bag. Charging the Mower 🔋Charge before first use. The mower ships in a low-charge condition and should be fully charged before operation. Connect the charger to an outlet Plug the charger into an appropriate AC power outlet. Connect the charger to the mower Connect the charger plug into the mower charging socket to begin charging. Check the charger light The charger LED illuminates red while charging. Unplug when fully charged The battery takes up to approximately 4.5 hours to charge. When the LED turns green, unplug the charger from the outlet and mower. ⚠️The charger does not automatically turn off when the battery is fully charged. Do not leave the mower plugged into the charger after the light turns green. Battery Indicator Guide LEDs Illuminated Battery Condition Green, Yellow, and Red More than 60% charged Yellow and Red More than 30% charged Red only Less than 30% charged; recharge before continued use Starting + Stopping 🚫Do not start in tall grass. Make sure the mower is not touching foreign objects, and keep hands and feet away from the rotating blade and ejector opening. Insert the safety key Insert the safety key into the slot before starting the mower. Raise the front slightly Hold the handle assembly with both hands and tilt the handle downward to slightly raise the front of the mower. This helps reduce lawn damage during startup. Start the mower Press and hold the safety lock button, then pull the switch lever toward you. Begin mowing Once the mower powers on, release the safety lock button and gently lower the mower into the cutting position. Stop the mower Release the switch lever. Wait for the blade to fully stop before moving, tilting, cleaning, or inspecting the mower. Cutting Height Adjustment ⚠️Remove the safety key before adjusting the height. Wait until the blade has completely stopped and wear gloves because the adjustment area is near the blade. Height Setting Cutting Height Low 1.2 in. / 30 mm Medium 1.93 in. / 49 mm High 2.5 in. / 64 mm Power off and remove the key Turn the mower off and remove the safety key from the slot. Remove the grass collection bag Remove and empty the grass collection bag before adjusting the mower. Place the mower on its side Carefully place the mower on its side to access the wheel axle positions. Set all four wheels evenly Move all four wheel axles to the same height position by pulling back on each rod axle and setting it into the correct position. Return to mowing position Place the mower back on its wheels, reattach the grass collection bag, insert the safety key, and resume normal use. 🌱Use the high setting for uneven ground or tall weeds. For thick or tall grass, start high and mow again at the desired height. Mowing Tips 1 Clear the mowing area first Remove stones, sticks, wires, toys, and other objects that could be picked up and thrown by the blade. 2 Slow down in thick grass Reduce walking speed in thick grass to help improve cutting and clipping discharge. 3 Follow the one-third rule For a healthy lawn, cut off one-third or less of the total grass length at a time. 4 Use safe slope direction Mow across slopes, not up and down. Do not mow inclines greater than 15 degrees. 5 Turn off before crossing gravel Release the switch lever before crossing gravel surfaces to reduce the risk of thrown stones. Care + Maintenance 🚫Remove the safety key before cleaning, repairing, or inspecting the mower. Confirm all moving parts have come to a complete stop. 1 Keep the mower clean After each cutting session, remove grass clippings and debris with a dry cloth or hand brush. 2 Keep handles dry Keep the handles dry, clean, and free from oil and grease. 3 Check hardware before use Check nuts, bolts, and screws for proper tightness before each use. 4 Inspect the grass bag Frequently inspect the grass collection bag assembly for signs of wear or damage. ⚠️Do not clean with running water or high-pressure water. Do not allow water to enter the mower interior, switch, plug mechanism, or motor. Blade Care 🚫The mower blade is sharp. Wrap the blade or wear protective gloves when handling. Remove the safety key before checking or replacing the blade. 1 Check the blade when cut quality drops If the mower is leaving a rough or uneven cut, the blade may be dull, worn, or damaged. 2 Minor wear may need sharpening If the blade is blunt or has minor wear, it may need to be sharpened. 3 Major wear requires replacement If the blade is bent, gouged, damaged, or heavily worn, replace it with the correct blade. 4 Use only the correct replacement blade The listed replacement blade model is MJ401C-BLD. Storage 1 Remove the safety key Always remove the safety key from the slot before storing the mower. 2 Clean before storage Clean the mower with a damp cloth or hand brush and remove grass buildup. 3 Inspect for wear or damage Check connections, screws, and the mower blade. Tighten or replace parts as needed before the next use. 4 Store indoors Store indoors in a dry, clean, cool area out of reach of children. Do not store next to corrosive materials such as fertilizer or rock salt. 5 Fold for compact storage Loosen the handle knobs on each side of the upper handle and fold the upper handle down. ⚠️Do not cover with a solid plastic sheet. Plastic coverings can trap moisture around the mower and may damage the unit. 🔋Battery storage tip: Never store the mower with the battery discharged. Recharge the battery immediately after it is discharged, and recharge every 6 months during long-term storage. Troubleshooting Guide Use these quick checks for common MJ401C concerns. Always remove the safety key before maintenance, cleaning, inspection, or checking that parts are in proper working order. 🔴 Mower Fails to Start Possible Causes Safety key is not inserted Motor/blade control is disengaged Battery is flat Mower deck is clogged with grass or debris Grass is too tall Solutions Insert the safety key Press the safety lock button first, then pull the switch lever Charge the battery Remove the safety key and clean the mower deck Set the mower to a higher cutting height and raise the front wheels slightly during startup If still not working, check warranty eligibility and route to warranty support ⏹️ Mower Stops While Mowing Possible Causes Battery is flat Grass is too tall Mower deck is clogged Overload protection system switched the mower off Solutions Charge the battery Reset the cutting height higher Remove the safety key and clean the mower deck Allow the mower to cool for 5 minutes before restarting 🌱 Mower Cannot Cut Evenly Possible Causes Lawn is rough or uneven Blade is not sharp enough Solutions Adjust the cutting height Sharpen or replace the blade if cut quality remains poor 🍃 Mower Cannot Mulch Properly Possible Causes Mower deck is clogged with grass or debris Grass is too wet Grass is too tall Blade is not sharp enough Solutions Remove the safety key and clean the mower deck Wait until the grass is dry Set the mower to the high position for the first pass, then mow again at the desired height Sharpen or replace the blade 💪 Mower Is Difficult to Push Possible Causes Grass is too tall to cut Blade or rear of mower is dragging through heavy grass Solutions Adjust the cutting height higher Use slower passes in thick grass If grass is very tall, mow once on high and repeat at the desired height ⚠️ Mower Vibrates at High Speed Possible Causes Motor shaft may be bent Blade is unbalanced Blade screw is loose Solutions Stop the motor and remove the safety key Inspect for visible damage Tighten the blade bolt if loose Replace the blade if damaged or unbalanced Do not continue using the mower if abnormal vibration continues 🔌 Charger Does Not Work Possible Causes Power failure Bad connection between charger plug and charger socket Solutions Check that the charger is plugged into a working outlet Reconnect the charger plug securely to the mower charging socket If still not charging, route to support Optional Accessories + Replacement Parts Item Model 10.6-gallon / 40 L grass collection bag MJ401E-10 Lawn mower side-discharge chute accessory MJ401E-DCA Replacement blade MJ401C-BLD Video Guide Frequently Asked Questions What is the MJ401C best used for? The MJ401C is intended for private residential grass cutting in small lawns and gardens. Is the MJ401C gas-powered? No. The MJ401C is a cordless battery-powered lawn mower. It does not use gas or oil during operation. What is the cutting width? The mower has a 14-inch / 35.6 cm cutting width. How long does it take to charge? The battery takes up to approximately 4.5 hours to charge. Unplug the charger once the indicator light turns green. Does the charger shut off automatically? No. The charger does not automatically turn off when the battery is fully charged. Unplug the charger when the LED turns green. How do I start the mower? Insert the safety key, press and hold the safety lock button, then pull the switch lever toward you. Once the mower starts, release the safety lock button while continuing to hold the switch lever. Can I mow wet grass? No. Do not operate the mower in rain, damp grass, or wet conditions. Wait until the grass is dry before mowing. What are the cutting height settings? The mower has 3 cutting height settings: Low 1.2 in., Medium 1.93 in., and High 2.5 in.. Why does the mower stop while mowing? Common causes include a low battery, grass that is too tall, a clogged mower deck, or overload protection. Charge the battery, raise the cutting height, clean the deck, and allow the mower to cool for 5 minutes before retrying. What replacement blade does it use? The listed replacement blade is MJ401C-BLD. How should I store the mower? Remove the safety key, clean the mower, inspect for worn or loose parts, and store indoors in a dry, clean, cool area out of reach of children. Recharge the battery every 6 months during long-term storage. What warranty does it have? The MJ401C is backed by a 2-year limited warranty for ordinary household use when purchased from Shop Joe or an authorized seller with proof of purchase. Related articles MJ504M 16-Inch Manual Quad-Wheel Reel Mower