If you continuously use a self propelled lawn mower, it will result in its blades getting worn out, blunt or broken. Should this happen, it will become untenable to continue using it.

You will, therefore, need to change the old blade with a new one. How then should you carry on with this exercise? Is it a complicated procedure? Can it be done by everyone?

This article is going to respond to all your concerns regarding the lawn mower blades. Please read through it. It contains the most current and updated information regarding this topic.

What is the procedure when changing the lawn mower blade?

⇒ Regular inspection.

Before changing the blade, make it a routine to carry out a regular inspection on the mower. You will be able to establish the extent of the damage every time you check on it. It will also give you an idea of when to change the blade, and whether to change or not.

There are a few steps that you will follow to access the blade beneath the mower. The blade is always covered because the user has to be protected. This blade can be so dangerous if left exposed especially when mowing the grass. The blade spins at a high speed when it is in use, hence it should always remain covered.

How to Change Lawn Mower Blade


How to change lawn mower blade?

⇒ Lift the mower deck.

The blade is always hidden behind the deck and it is not visible when the mower is upstanding. There are many other components under the deck. These include the carburetor and the oil compartment. You should, therefore, lift the mower gently. Do not tilt is so much as the oil may spill and damage other parts, especially the carburetor and the engine. Consult your manual to find out the best direction to tilt the mower. While other mowers can be best tilted backward, others can be tilted sideways. The manual should be able to guide you appropriately on this.

⇒ Take off the spark plug.

This component is responsible for electric transmission in the mower. Do not attempt to do any repairs when this part is connected to the mower. It can cause an electric fault even if the engine is already switched off. The plug may not cause an electric shock all the time, especially if you tilt the mower properly. However, it is always better to be safe than sorry. I would just advise you to take it off before you start the job.

⇒ Remove the old blade.

The blade is held by a bolt. Use a wrench to turn it in an anticlockwise direction until it becomes loose. Turn the wrench using one hand while using the other hand to hold the blade to keep it from rotating. Remember to keep a close eye on the bolt so that you do not lose the washers, especially if they are still useable. As a matter of precaution, do not hold the sharp part of the blade. The sharp edge can hurt you, hence you should exercise some care.

Do not lose track of how the blade is installed. You will need that formula in installing the new blade.

When the bolt and washers are out, pull out the blade gently. It might become difficult to get it off because the blade might have been there for long. When you have removed the blade, carry out some cleaning before putting back a new one. Where possible, apply oil to those parts that need to be oiled before placing a new blade. Have the new blade ready for installation.

⇒ Install the new blade.

By this time, you must have bought a new blade and all the necessary components. Whenever you want to carry out a replacement, you must ensure that you have everything ready beforehand.

Mount the new blades in the appropriate direction. The process should generally follow that of unmounting the old blade. Mower blades are of different designs hence their mounting and unmounting might be slightly different. Always refer to the user manual if you are not sure of how it should be done. It is always a good idea to wear some protective gear when handling mower blades. You should consider protecting your hands by wearing hand gloves.

Once the blade has been mounted, insert the washers and the mounting bolt. Tighten the combination by the use of a wrench. Use one hand to turn the wrench while holding the blade using the other hand. You should use a piece of wood to hold the blade from rotating instead of the hand. This is even safer than when using your hand, especially if you do not have the gloves on. Insert a piece of wood between the blade and the mower, the blade will jam. You can then tighten the bolt, but remember to remove the wood when you are done.

⇒ Rotate the blade and check it for play.

This should be able to tell you if you inserted it correctly or not. If the blade is steady, then you would have accomplished the task, otherwise, you would need to redo it. Return the mower to its normal standing position and let it remain so for about a minute. This is to make the oil return to the motor. If you start the engine before the oil gets back to the motor, then you will experience motor damage.

  • Check for the oil limits and ensure that it is not low. If the oil has been overused, you will need to replace it as well.
  • Check the mower’s gas tank and refill it if need be. For a mower to operate optimally, it should have a good, sharp blade, gas and appropriate oil levels.

These are some of the things to check every time before you use this tool. Once you are done with these simple checks, and everything is okay, then your mower will be ready for use.

⇒ Test the mower.

Some of the checks to confirm here include looking into the air filter and reattaching the spark plug. Switch on the engine and test the mower. Do not use it to mow until you establish that it is fit for use. Try cutting some grass as you check on the mower. If everything is okay with the mower, then you can deploy it fully for the work.

Is it costly to replace a lawn mower blade?

Generally, the cost will depend on how you source for the parts, the seller’s cost and the labor cost. In most instances, it should not cost you more than $20 to do the entire work. If it exceeds this cost, then there must have been some extra things which you have incurred.

How do you know that you have not put the blades upside down?

Most replacement blades are stamped to indicate which side face down. This should be able to guide you so that you install it properly and as per the requirement. If it is not indicated, you can always refer to the user manual for more information.


You should always take good care of your machine. Replace the blade as often as need be. When it is worn, broken or old, do not hesitate to get a new one. Always run some health checks on the machine to establish the extent of its usefulness. Exercise some care when replacing the mower’s blade so that you do not end up hurting yourself instead.


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