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How to Replace A Lawn Mower Blade

How to Replace A Lawn Mower Blade

Like your other power equipment, lawn mowers need yearly maintenance and replacement parts to continue functioning well. Over time, your lawn mower’s blade will begin to wear down. A dull blade can make a mess of your grass, making it much less appealing. Worst of all, grass that is cut improperly can begin to develop bare patches, resulting in a pretty sad looking yard. It might be that your blade has simply become dull, in which case you can have it sharpened at a power equipment shop near you (or do it on your own if you’re proficient with a bench grinder). Eventually, the blade will need to be replaced after several bouts of sharpening. This is also true if your blade has been chipped or damaged. Luckily, this process is fairly easy and doesn’t require professional help. Plus, lawn mower blades are inexpensive, so you won’t have to break the bank to make this repair. Here’s how to change your lawn mower’s blade to get your machine running as good as new again.

Tools Required

  • Socket Wrench
  • New Mower Blade
  • Shop Gloves
  • Protective Eyewear
  1. Remove the gas from the mower. Either use all the gas in the mower or siphon it out with a hose, turkey baster, or pump. This will prevent gas spillage.

  2. Position mower for replacement. Tilt the mower back using the handle so that it’s resting on the two back wheels. Prop it with something so that you can get to work. A car jack, box, wood block, or something else will do.

  3. Disconnect the spark plug. This is a precautionary step to prevent the engine from accidentally turning on or an electrical flare-up. Check your owner’s manual if you aren’t sure where the spark plug is located on your lawn mower.

  4. Remove the blade mounting bolt. Hold the blade in place with a gloved hand or lodging a block of wood in between the blade and mower deck. Using a socket wrench, unscrew the bolt. Place it and any other washers or mounting hardware in a safe place close by. Note the way the blade was positioned before removal. You will install the new one in the same way. Taking a photo of the blade may make this easier. Your owner’s manual should have a graphic for this as well.

    Discard the old blade or have it sharpened for future use.

  5. Mount the new blade. Install the new mower blade in the same position that the old one was in. Check your owner’s manual for the torque specifications for the bolt. This cannot be too loose or tight.

  6. Check the new blade. Now, test out the new blade by moving it up and down. It should not feel shaky or loose, but very stable and fluid. Clean the underside of the deck for a fresh start. If you have it, apply a coating of silicone spray to help manage grass clipping build-up. Lower the mower back down and allow oil to return to the motor.

  7. Refill the gas tank. Ensure no gas soaked into the air filter. If it did, replace the filter. Gas the mower up and perform a pre-check.

Your lawn mower should now cut grass much better without the need to go back over areas. You can expect this process to take less than an hour! As long as you properly care for the mower, your new blade will be in good working order for many years.