Knowledge Base

How to Change a Lawn Mower Blade

By December 20, 2016 No Comments

So, the question that’s often asked is when is it time, or how do you know it’s time to change your lawn mower blade? The easy answer is when the blade is no longer effective at cutting then it’s time to change it. This is very easy to spot because there will be spots in the area you’re cutting where you’ve already gone over it but the grass remains uncut. That’s when you know it’s time to change the blade.

The good news is changing a lawn mower blade isn’t all that hard to do. In this article, I’ll go over the simple steps to help you do it.

  1. Gain access to the blade by lifting the lawn mower.

(Note: Be careful not to tilt it back too far as this will result in creating an oil spill.) Raising the mower to gain access to the blade is a job most safely done with a partner. You want to tilt the mower back toward the handle and have your partner hold it in his position. If you don’t have the help of a partner something can be used to prop it in place. You should empty the gas tank before tipping the mower.

  1. Make absolutely certain the spark plug is disconnected before working with the blade.

This ensures that the mower cannot be started accidentally and also keeps the spark plug from coming in contact with gasoline.

  1. Removing the blade mounting bolt.

To remove the blade mounting bolt, you’ll need an appropriately sized socket wrench. Use one hand to remove the bolt while using the other to keep the blade from moving. Before completely removing the blade you should make a note of its position because you need to install the new one in the same position.  It is standard for the sharp end of a mower blade to turn counterclockwise. However, you’ll want to consult your mower’s owner’s manual to be sure of this for your specific model.

If you’re not sure what type of blade to buy you should check your owner’s manual. Replacement lawn mower blade kits are available for purchase at most any reputable hardware store.

It should be noted that it’s sometimes possible to recycle your old blade by sharpening it, but if it has really taken a beating is missing chunks it’s probably best to buy and install a new one.

  1. Make sure the new blade is mounted in the correct direction.

The best way to do this is to visually line up the lawn mower blades the same way they were before. You can at your option reuse the old hardware when installing the new blade, or buy it all new. Either way, take care not to overtighten the bolt as this may cause damage to the newly installed blade. Most blades are standard sized universal fit, however, take the time to check the length of the new blade against the old one. Check both the length of the blade and the clearance from the mower deck to see that they are the same. When installing the new blade, it will be sharp so for safety it’s best to wear a pair of thick working gloves, with a block of wood wedged between the mower deck and the blade to keep it from turning while you’re working with it.

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