How to Sharpen and Care for Your Walk Behind Lawn Mower Blade

Maintaining sharp lawn mower blades is important to a healthy, lush lawn.  Regular use can cause blades to wear and even warp or bend.  If your blades are dull or worn from mowing activity, you can sharpen or replace them yourself.  However, if you hit something and the mower beings to shake, you should take it to a MTD service partner to have the blades replaced and balance adjusted.

It's important to perform regular lawn mower blade maintenance at the start of each season.  Inspect the blade adapter for cracks, and check the condition of your lawn mower blades.  The blade adapter should also be checked periodically throughout the season, especially if you strike a foreign object.  Replace blades when necessary and follow the steps below for blade service that will extend the life of your mower.




Step 1: Making the mower safe for lawn mower blade maintenance

Disconnect the spark plug wire from the spark plug to prevent the lawn mower from starting during blade maintenance.  Turn the mower on its side, making sure that the air filter and the carburetor are facing up.

Step 2: Attaching the blade removal tool

The blade removal tool stabilizes your lawn mower blades so you can safely remove them.  Place it over one side of the blade and attach it to the side of the walk-behind mowing deck.

Step 3: Removing lawn mower blades

Remove the bolt and the blade bell support which hold the blade and blade adapter to the engine crankshaft.  Then remove the lawn mower blade and adapter from the crankshaft.

Step 4: Using a mower blade sharpener

If the blade is dull but in otherwise good condition, you can use a mower blade sharpener to get it ready for the season.  The blade can also be sharpened with a file or on a grinding wheel.  When sharpening the blade, follow the original angle and grind.  Using a mower blade sharpener and balancer can help you grind each cutting edge equally to keep the blade balanced.  Do not attempt to sharpen the blade while it is still on the mower.

Step 5: Testing for balance

To test for balance, place the lawn mower blade on a round shaft screwdriver.  Remove metal from the heavy side until it balances evenly, or use our blade balancer kit.

Step 6: Prepping to put the lawn mower blades back on

Lubricate the engine crankshaft and inner surface of the blade adapter with light oil. Slide the blade adapter onto the engine crankshaft.

Step 7: Putting lawn mower blades back on

Place the blade on the adapter such that the side of the blade marked "Bottom" (or with the part number) faces the ground when the mower is in the operating position. Make sure that the blade is aligned and seated on the blade adapter flanges.

Step 8: Attaching lawn mower blades

Place blade bell support on the blade. Align notches on the blade bell support with small holes in the blade.

 

Replace hex bolt and tighten hex bolt to torque recommended in your operator's manual. To ensure safe operation of your mower, periodically check the blade bolt for correct torque.

Step 9: Get ready to mow

Right the mower and reconnect the spark plug.  Add fuel and you're ready to go!

 

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