Black & Decker mm1800 Electric Mower Fan and Blade Spacer Repair


A critical component of maintaining our little backyard (and front yard) farm is cutting and mowing the bits between the planting beds. I don’t like messing with gasoline engines, so I decided to get an electric string trimmer and mower.

As with any yard equipment you use frequently, my Black & Decker mm1800 Corded Electric lawn mower needs a few repairs. I’ve been using it now for 2 1/2 years without repairs, so it is due for a little attention.

The Black & Decker mm1800 electric mower (and all the other electrics in the Black & Decker product line) has a floating blade that sits on top of a fan unit on the motor shaft held down with a square washer and plastic blade insulator/spacer. The blades of the fan can be broken-off if you mow over a rock or other hard items (a ‘fairy house’ made out of broken pottery was the culprit the last time). The broken pieces bounce around under the mower and hit the plastic fins. Mine had just 4 fins remaining which throws off the balance of the blade unit causing the mower to vibrate like crazy.

Replacing the fan only requires 2 tools. You need a pair of adjustable Channellock pliers and a socket wrench to remove the bolt that hold down the blade and fan assembly. Once that is off, replacing the fan only takes a few seconds. This is also a good time to replace/sharpen the blade.

Other than replacing the blade, the fan, and the fan spacer, this is the only maintenance this mower has required in the entire time I’ve owned it. No filters, gas, oil, spark plugs, gaskets, or any of the other parts that need upkeep on a typical gas mower.

Andrew Seltz

Andrew was born in Michigan, raised there and in Tennessee, and has since lived outside Orlando, in Chicago, New York City, and now Birmingham, Alabama. He produces videos and websites for a living and is married to a beautiful, generous, loving woman who also happens to be a talented actress and writer - They have two daughters.

5 thoughts on “Black & Decker mm1800 Electric Mower Fan and Blade Spacer Repair

  • April 27, 2015 at 3:42 pm

    Great video, but I don’t think this is my problem. I hit a metal pipe that was sticking our of the ground (it was hidden by the grass. The blade won’t turn at all and the mower just makes a small humming sound when on.

    I followed your directions and when I took off the fan, I did see one of the plastic blades was broken off. Another site mentioned that to make sure this is the problem, before wasting money on the parts, to try to turn on the machine with the blade and fan off and to see if it works. But again, only a gentle hum. Any ideas? Thanks!

  • May 2, 2015 at 4:44 pm

    Glad the video was helpful. I never hit anything that rigid, so I don’t have any first hand experience with the kind of damage it would do to the mower.

  • October 7, 2016 at 11:28 am

    great video, i really love black and Decker as a gardening tool brand

  • May 2, 2020 at 2:23 am

    Thank you for this video, it is helpful specially for a new lawn mower user.

    With help of a box spanner, remove the nut holding the blade. Usually the nut will be unlocked in the reverse to direction of rotation of engine. You may engage the screwdriver in the cooling fan of engine to stop rotation of engine.

    If you find that you are using too much force to unlock the nut, put one or two drops of rust removing chemical, and try after 30 minutes

  • May 17, 2020 at 6:57 pm

    Glad you found this helpful. The big issue with the electric mower blade wasn’t a rusted bolt, it was the lack of a keyed connection between the blade and the drive shaft. After years of using a chunk of wood against the blade to brace the shaft, I had to shift my thinking a bit. Old habits die hard.

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