How to Change a Lawn Mower Blade?

A mower’s blade can be rightly said to be the ‘out of sight, out of mind’ component of a lawn mower. If anything, its work entails continuous spin down there while mowing the lawn all season. What many of us fail to realize is that once the lawn mower blade turns dull, it can commit great injustice to the grass thus making it susceptible to diseases.

While you can opt to sharpen your mower’s blades severally in a bid to extend their life, it won’t be long before this proves ineffective and inefficient. A dull lawn mower blade stresses the engine when cutting the grass. This results into more fuel, damage beyond repair and untold overheating. As such, it’s vital to ensure lawn mowers blade stays in good condition every time.How to change a lawn mower blade

Considering that lawn mower blades wear out with use, it’s advisable to occasionally change them in order to make the mower more efficient. Changing a lawn mower blade is quite easy and as long as it’s approached correctly, it takes a few couple of minutes. It’s also a key maintenance task that you’ll have to do from time to time.

Just like with other maintenance routines, we advice our readers to frequently check their lawn mower blades, if you sight something amiss, better change it soonest.

How to Change a Lawn Mower Blade

Signs You Need To Change a Lawn Mower Blade

Here are signs that your mower’s blade has taken a beating after lengthy mowing sessions in the lawn:

  • It’s bent. This normally happen when you accidentally mow over large objects and rocks. A bent mower may cause destruction of the bearings thus causing premature damage.
  • It’s been under use for more than two years. Generally, a mower’s blade ought to be changed after 1-2 years of usage. This helps it perform better as well as ensure it’s safe for usage.

Signs You Need To Change a Lawn Mower Blade

  • Presence of dents, gouges or missing pieces. These are a major safety hazard. Damage of lawn mower blades’ increases the risks of small debris and pebbles being propelled at a high dangerous speed. This can result into fatal accidents.
  • It remains dull even after being sharpened. Dull blades tear the lawn instead of cutting it. This results into ragged tips. If the blade still doesn’t perform as expected even after being sharpened, it’s time you changed it. However, frequent mower blade’s sharpening can weaken them; make them brittle and more prone to hazardous damage.
  • Presence of excessive vibration while mowing. It easy to notice a dull mower by the irregular and ugly patterns made in the lawn.

Why Change a lawn mower blade?

We recommend a change of mower blades after a considerable times of usage or if they’re damaged. Frequent sharpening is another big reason you ought to change a mower’s blade.

You can replace the blade with a new set or used blades that are still in reasonably good conditions. The decision to change lawn mower blades should be based on:

  • Torn out grass  or unclean cut

If the tips of your grass look torn out and uncleanly cut, the mower’s blades are to blame. There are high chances that they’re damaged and should be replaced soonest. In such a case, consider changing the lawn mowers blade to avoid future harm to your grass.

Why Change a lawn mower blade

  • Uneven length of grass: This is a clear indication of the need to either sharpen or change a lawn mower blade. Normally, a lawn mower is expected to cut grass at similar height. However, if they’re dull or damaged, you may have to move it myriad times in the lawn to get your desired outcome. Usually, these efforts are futile.
  • State of the lawn mower blades: Undoubtedly, dented cutting edge of lawn mower blades can never cut the grass smoothly. The dents could have been caused by dirt, moisture or even sand in the lawn. Unfortunately, repeated sharpening of the blades may worsen the situation by weakening their metal. As such, more than often, changing the lawn mower blade is usually a better option.

How Often To Change a Lawn Mower Blade?

At this juncture, chances are you’re wondering about how often you should change a lawn mower blade. Well, if you’re an average mower, endeavor to change it at least once a year, especially at the beginning of a new season. However, if they’re damaged, you can change them anytime.

Before starting the process of changing a lawn mower blade, kindly start by inspecting the user’s manual to get insights about its warranty, model and safety instructions of such lawn mowers.

Do’s before Changing a Lawn Mower Blade

  • Check your user’s manual.
  • Uphold the safety precautions including use of correct PPE’s.
  • No experience, consult.

How to Change a Lawn Mower Blade?


  • A lawn mower to work on
  • Replacement mower blade.
  • To fit attaching bolt(s).
  • Approximately two cylinder blocks. To place the lawn mower.
  • Gloves (optional)
  • Safety glasses/goggles (optional)

Evidently, mower blade’s mounting designs vary depending on the models. If you’re an amateur in matters lawn mower blades, we recommend that take a video/ picture of every step to ensure you get the restoration right. The steps towards effecting their change are usually similar. These are:

1. Get to the Bottom of Things

1. Get to the Bottom of Things

Use sturdy cylindrical blocks that are able to support the weight of your mower. This should grant you access to the blade underneath and ensure zero movement as you work on the mower.

2. Disconnect the spark plug

2. Disconnect the spark plug

The removal of the spark plug ensures the mower doesn’t start during the process. However, this isn’t a big deal if you hold the mower properly. But, as we’ve always told you, it’s better safe than sorry.

3. Turn the Mower On Its Side Then Drain The Fuel Tank

3. Turn the Mower On Its Side Then Drain The Fuel Tank

This side should be the one that doesn’t have the carburetor. Ensure that the oil and gas caps are tightly sealed before turning the mower. This ensures there’s no spillage during the process.

4. Loosen and Remove The Mower Blade’s Fasteners

4. Loosen and Remove The Mower Blade’s Fasteners

This normally involves removal of one or two bolts holding the blade to its shaft. A wrench is very handy in this. Be keen not to lose any mounting hardware or washers that could get reused.

5. Remove the old mower blade

Using the right wrench, turn the blade’s bolt clockwise to loosen it. As you’ll notice, the blade might turn as you turn the wrench. To avoid this, use your hand to deter it from turning while loosening. The gloves prove handy in this.

6. Putting on the New Blade

Most lawn mower blades are designed in a way that that the blade can only be installed in the correct position. Fortunately, a few quick checks are all it takes to rectify a wrongly installed mower blade.

Putting on the New Blade

Come what may, ensure you don’t install your new blade upside down. If you do so, it will just not cut your grass. If you had taken a video/picture trail of your doings, they will come in handy in getting right the correct fixation side.

7. Check the blade for play

After getting the right blade orientation, install the bolt back to the mower’s shaft and fasten it through the blade. Ensure there’s zero wobble when you move the blade up and down. This firm fixation ensures there’s no movement while you’re mowing your lawn.

8. Refill the gas tank and do a pre-check before mowing

Refill the gas tank and do a pre-check before mowing

Inspect the air filters to ensure that the oil never saturated the foam filter  then reattach the spark plug wire. Thereafter, you should be able to start your lawn mower and continue with your mowing activities. Just that and you’re done, quite easy, isn’t it?

Mistakes to Avoid When Changing Lawn Mower Blades

  • Failing to turn the mower upside down before emptying the fuel tank.
  • Changing the mower’s blade whereas it can be sharpened.
  • Fixing it in the wrong direction.
  • Trying to do-it-yourself even with zero experience. Consulting has never harmed anyone.
  • Failure to know the type of blades. There is lawn mower blades designed for mulching, bagging or discharge. There’s no one single-fit. Be keen on manufacturer’s specs.


You’ve seen how easy it is to change a lawn mower blade, isn’t it? So, why not take this chance to save money on the same by doing it yourself? Your grass will thank you for it.

When it’s all said and done, bear in mind that lawn mowers aren’t toys. Therefore, always be sensible when changing their blades. Honestly, it would be so sad to have you lose your finger. So, ensure you keenly follow the above steps and have you mower give you optimal service whilst keeping your hands safe. Thank us for it.

About Jennifer Igra

Growing up in Brooklyn, New York City known for it’s green gardens. Jennifer, a 30 year old gardener and green living fanatic started Igra World to share her gardening journey and increase gardening awareness among masses. Follow Igra World to improve your gardening skills.

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