You could have probably sharpened the blade a summer or two ago. Perhaps you've noticed the blade isn't cutting as well as it used to on your MTD lawn mower. Replacing the blade is relatively simply and chances are you've had the tools to remove it and sharpen it at the end of each mowing season. Replacement blades are cheap enough, so why not remove the old one and replace it yourself and save yourself some money from the local small engines repair shop? Perform this repair when the mower is out of gas.
How to Change an MTD Lawn Mower Blade
Unplug the spark plug wire from the MTD lawn mower. Make sure it cannot come in to contact with the spark plug during the blade replacement procedure.
Tip the mower upside down so the mower blade is facing upward.
Wedge the 2-by-4 inch block of wood into the blade cavity of the mower. Turn the blade manually counterclockwise until the blade locks against the block of wood.
Remove the arbor bolt from the center of the old blade with the ratchet and a socket. Remove the blade and the washer.
Install the new blade, making sure to seat the hole in the center of the blade around the arbor. Also, make sure the cutting edge of the blade is facing the top of the mower and the flat edge of the blade is facing the bottom of the mower.
Rotate the blade clockwise until it seats against and anchors against the 2-by-4 inch block.
Replace the washer and arbor bolt and tighten tightly. You do not want a blade flying off the MTD lawnmower because you didn't tighten the arbor bolt tight enough.
Flip the MTD lawnmower over and reattach the spark plug wire to the spark plug. Fill the mower with gasoline and test run it to make sure the blade does not vibrate.