Brand: BLACK & DECKER
Category: Lawn Mower
Document Type: Manual
Language: EN
Available Languages: EN , ES
Manual for MM875
Uploaded: April 20, 2026, 7:47 p.m.
Manual Publish Date: 2008-01-01
Warranty Information
Black & Decker (U.S.) Inc. warrants this product for two years against any defects in material or workmanship.
Operating Instructions
To Start Mowing: Ensure the mower is assembled correctly. Plug in the extension cord to the mower and then to the electrical outlet. With the switch lever engaged, pull it towards the handle to start the mower. Release the lever to stop.
Cutting Height Adjustment: Use the one-touch wheel height adjustment system. Turn off the mower, wait for the blade to stop, and unplug. Adjust all four wheels simultaneously by squeezing the finger grip and moving the wheels to the desired height. Ensure the deck is securely locked.
Mulching vs. Discharging: To mulch, ensure the mulch insert is installed and the rear door is closed. To discharge, remove the mulch insert and attach the discharge chute. For bagging, attach the grass catcher.
Safety Precautions: Always keep hands and feet clear of the blade. Never operate without safety guards in place. Keep the area clear of bystanders and pets. Always wear appropriate footwear and eye protection.
Troubleshooting and error codes
| PROBLEM | CORRECTIVE ACTION |
| Motor will not start | - Check fuse or circuit breaker to ensure power is to outlet - Check extension cord with another electrical device to ensure cord is good. - Call customer service representative 1-800-544-6986 |
| Motor keeps slowing down | - The underside of the mower may be plugged with clippings. Turn mower off, wait for blade to stop and UNPLUG mower and clean out. - Grass may be too tall, try pushing at a slower pace, or raise cutting height. - Check blade sharpness and balance, and correct if required. - If mulching, there is too much grass. Turn mower off, wait for blade to stop and UNPLUG mower and attach discharge chute to disperse grass |
| Runs but poor cut results | - The blade may be dull. Turn mower off, wait for blade to stop and UNPLUG mower and carefully check for sharpness. - Blade may be damaged (bent or badly chipped). Turn mower off, wait for blade to stop and UNPLUG mower and replace if necessary. - Grass may be too high or thick for cutting height. Turn mower off, wait for blade to stop and UNPLUG mower and raise cutting height. |
| Excess vibration | - Blade may be loose. Turn mower off, wait for blade to stop and UNPLUG mower then check blade for tightness. - Blade may be damaged (bent or badly chipped). Turn mower off, wait for blade to stop and UNPLUG mower and replace if necessary. - Blade may be unbalanced. Refer to blade balancing section of instruction manual. |
| Mower is hard to push | - Mower is too close to the ground with the amount of grass being cut. Turn mower off, wait for blade to stop and UNPLUG mower and raise cutting height. - Turn mower off, wait for blade to stop and UNPLUG mower and check wheels and axles to ensure all are rotating easily. |
| Mower leaves clumps of grass | - If mulching, there is too much grass. Turn mower off, wait for blade to stop and UNPLUG mower and attach discharge chute to disperse grass |