Mower Losing Power When Blades Engaged: Causes & Solutions

Good day!

Mowing the lawn is an essential task when maintaining a beautiful yard. However, it can be frustrating when you notice your mower losing power when blades are engaged. 

This problem can cause uneven cuts, leave patches of uncut grass, and slow down your mowing process.

This article will discuss the primary causes of this problem and recommend practical solutions to fix it.

Mower Losing Power When Blades Engaged: Common Causes 

Mower losing power when blades are engaged is a common problem that can be frustrating. Here are the common causes of this problem:

Dirty/Clogged Air Filter

A dirty or clogged air filter is one of the most common causes of your machine losing power when blades are engaged. 

The air filter prevents dirt and debris from entering the engine. However, when it becomes clogged, it restricts airflow. So it causes the engine to lose power. 

Dirty lawn mower air filter

Contaminated/Stale Gas

Another common cause of your lawn mower not running at full power when blades are engaged is contaminated or stale gas. 

The gas may have gone bad if your machine has been sitting for a while. Consequently, it can cause the engine to lose power. 

Additionally, if you accidentally add contaminated gas to the tank, it can also cause issues.

Spark Plug Is Dirty

A dirty or faulty spark plug can also cause your equipment to lose power when blades are engaged.

The spark plug ignites the fuel in the engine. However, it becomes dirty or faulty, causing misfires and power loss. Consequently, your lawn mower loses power under load eventually.

Too Much/Too Little Oil

Too much or too little oil in your machine can also cause it to lose power when the blades are engaged.

Too much oil can cause the engine to become flooded and malfunctioning. Meanwhile, too little fuel can cause the engine to overheat and seize up. 

The fuel/oil issues

Clogged Fuel Filter

The fuel filter is a vital component of your vehicle. Maintaining the engine’s optimal performance is critical to prevent dirt from entering it. 

The filter’s primary function is to clean the fuel that enters the engine, ensuring it is free from impurities. 

However, over time, the fuel filter can become clogged. Hence, it may cause a loss of power in the engine. 

It can lead to a decrease in fuel efficiency and engine failure. Consequently, it causes the engine to lose power when it becomes clogged. 

Blocked Carburetor

When a carburetor is blocked, it can cause a mower to experience some difficulties and lose power when blades are engaged. 

The carburetor’s primary function is to mix air. After that, it combines fuel to create a combustible mixture for the engine. 

When it gets blocked, the carburetor can cause misfires and power loss. That’s because the carburetor can no longer perform its task effectively. 

Blocked Carburetor Lawn Mower

Mower Losing Power When Blades Engaged: Solutions 

After finding the leading causes, it’s time to fix this issue! Consider the following methods:

Keep Your Grass Short

As mentioned above, one of the most common reasons for a lawn mower losing power when cutting is that your grass is too long. 

When the grass is too long, the equipment has to work harder to cut it. It can cause it to lose power. It could also make the machine blades blunter quickly, resulting in a poorer quality cut. 

Therefore, it is vital to keep the grass short by mowing more frequently, especially during the growing season. 

It prevents the mower from losing power and ensures a better quality cut. Additionally, mowing more frequently helps to prevent grass clippings from accumulating on the lawn. 

Mowing more frequently can chop the grass clippings into smaller pieces that can quickly decompose and provide nutrients to the soil.

Furthermore, another way to prevent the machine from losing power is to ensure the blades are sharp. 

Dull edges can cause the device to work harder and lose power, so it is vital to sharpen them regularly. 

These steps can help your equipment remain in good working condition. Hence, your lawn will look healthy and neat.

Which is the best mower for thick grass?

Sharpen The Blades

Flat blades can’t cut your grass as efficiently as sharp edges, so more power is required to get the job done. 

It puts additional strain on the engine. So it can cause your machine to lose power or stall. 

You will need to sharpen the edges to fix this problem. You can do this yourself with a sharpening stone.

However, take the time and do it carefully to ensure you sharpen the blades evenly. Alternatively, you can take the edges to a professional to hone them. 

Check The Spindle

You must check the spindle regularly to ensure your mower works at its best. 

You should turn off the machine and remove the blades. Once the edges are off, inspect the spindle for any signs of wear or damage.

If you notice any issues, address them promptly to prevent further damage to your equipment. 

Replacing the spindle with a new one is often the best, ensuring the machine operates optimally. 


What Happens If A Mower Blade Is Unbalanced?

An unbalanced mower blade can cause several problems, as shown below:

  • A decrease in performance
  • A reduction in fuel efficiency

Does The Position Of Mower Blades Matter?

Yes! The position of the blades is essential in determining the quality of the cut. Generally, the blades should parallel the ground to achieve a clean and even cut. 

If the edges are not parallel, they may scalp the lawn, leaving it with uneven, unsightly patches. 

Additionally, improperly positioned blades can cause damage to the grassroots, making it susceptible to diseases and pests.

Check this video to install the blade correctly:

Why Do Mower Blades Need To Be Sharp?

The short answer is yes! A sharp mower blade is crucial for maintaining the health of your grass. Dull edges may tear your grass rather than cutting it cleanly, leading to uneven growth and increased disease risk. 

When the blades are dull, they also require more power to cut your grass, increasing fuel consumption and wear and tear on the machine’s engine. 

In addition, dull edges cause the grass to turn brown, making it less attractive.

Final Thoughts

Mower losing power when blades are engaged is a common problem that can be frustrating when trying to keep your lawn looking nice. 

Understanding the causes of this problem can help you fix it and get back to mowing your lawn efficiently. 

Remember to keep your grass short, sharpen the blades, and check the spindle to fix the issue and get your machine running smoothly again. 

With some maintenance, you can keep your lawn looking beautiful all season long. Thank you for reading!

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