How to Change the Mower Blade of a Lawn Boy

In the midwest, an old saying exists about how you can almost "hear" corn growing during the heat of the summer. It's the same way with a well-fertilized lawn during the spring. To maintain a plush, well-groomed look to your yard, you sometimes need to mow twice a week during rainy, peak growing periods. Anyone with a Lawn Boy mower knows such frequent cutting can dull your mower blade in no time. Fortunately, changing the mower blade on your Lawn Boy takes only a few minutes, particularly if you have a sharpened blade waiting in reserve.

Hand holding socket wrench
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Step 1

Wait until the engine of your mower has cooled and you have little or no fuel in the mower's gas tank before starting this process. Turn the mower over on its right side on a hard, non-grassy surface.

Step 2

Wedge a wood block underneath the mower and the blade so the blade cannot move. Unscrew the bolt with a socket wrench, using a counterclockwise motion. Remove the captive washer, as well, and place it and the bolt off to the side.

Step 3

Slip off the green outer plate from the blade assembly and pull off the old blade, which can be sharpened using an electric grindstone.

Step 4

Position the newly-sharpened blade or a reserve replacement blade so that the curved ends of the blade point upward. Reinstall the green outer plate.

Step 5

Reposition the wood as it was before to ensure the blade does not move. Twist on the captive washer and bolt in a clockwise manner, using a torque wrench to tighten to a snug, 60 foot-lb. setting. Remove the wood block and place the mower upright.