How to Remove Lawn Mower Spark Plug: A Step-by-Step Guide.

How to Remove Lawn Mower Spark Plug A Step-by-Step Guide
How to Remove Lawn Mower Spark Plug A Step-by-Step Guide

To remove a lawn mower spark plug, disconnect the spark plug wire and use a spark plug socket to remove the spark plug. Removing the spark plug from your lawn mower is a simple task that requires a few basic tools.

A spark plug is a key component of a gasoline engine, and it helps in starting the engine by igniting the fuel. Over time, your lawn mower’s spark plug may become worn or damaged, limiting the engine’s performance, leading to increased fuel consumption, or making it more difficult to start the engine.

If you presume that your spark plug is causing issues, it may be necessary to replace it. In this article, we will go over how to remove a lawn mower spark plug using basic tools.

Step 1: Preparation

Removing a spark plug is a simple task that anyone can do, even those with small to no experience with lawnmowers. However, it is important to follow the correct steps to avoid costly mistakes. Here’s a step-by-step guide to removing a lawn mower spark plug.

Explanation Of Why It Is Necessary To Disconnect The Spark Plug Wire

Before you start, it is essential to disconnect the spark plug wire to ensure your safety. Failing to do so may result in accidental ignition, which could lead to severe burns or injuries. Disconnecting the spark plug wire will prevent the lawn mower from starting accidentally while you’re working on it, keeping you safe.

How To Locate The Spark Plug On The Lawn Mower

To remove the spark plug, you must first locate it on your lawn mower. To do this, you’ll need to:

  • Direct to your lawn mower’s user manual to determine where the spark plug is located, as this varies by model and brand.
  • If you’re unable to find the spark plug located in the user manual, look for a thick wire that leads away from the mower’s engine. The wire should end with a cylindrical or square-shaped object that will be the spark plug.

Tips On How To Clean The Area Around The Spark Plug Before Removal

Before removing the spark plug, you must clean the area surrounding it. This is because waste and dirt can accumulate in the gaps around the spark plug over time, making it difficult to remove it. Here are some tips on cleaning the area:

  • Use a soft-bristled brush to remove any debris and dirt around the spark plug.
  • Gently tap the sides of the area around the spark plug with a rubber mallet to knock loose any stubborn debris.
  • Use a can of compressed air to blow away any remaining debris or dirt to ensure a clean work environment.
  • Keep a clean, lint-free cloth handy to wipe away any remaining dirt or debris.

By following these steps, you can remove your lawn mower’s spark plug safely and efficiently, and without causing any damage to your machine. Remember to always take proper safety protection and refer to your user manual for any additional guidance or safety measures.

Moreover, explore: How to Make a Lawn Mower Faster?

Step 2: Removing The Spark Plug

How To Use A Spark Plug Socket And Ratchet

Once you have identified the spark plug and its location, the next step involves using a spark plug socket and ratchet to remove it. Here is how to go about it:

  • Ensure that the engine is off and there is no risk of the mower accidentally starting. You can unplug the spark plug wire to prevent any accidental electric current from flowing.
  • Identify the correct size of the spark plug socket that fits the spark plug. The socket should be attached to the ratchet.
  • Place the socket over the spark plug and make sure it fits snugly.
  • Turn the ratchet counterclockwise to loosen the spark plug.

Explanation Of How To Turn In A Counterclockwise Direction To Remove The Spark Plug

Turning the spark plug counterclockwise can sometimes be challenging, particularly if the plug is old and rusty. Here are some tips to help you turn the plug smoothly:

  • Hold the ratchet handle firmly and apply steady pressure in a counterclockwise direction to loosen the plug.
  • If the plug is stuck, try using a penetrating oil such as wd-40 to loosen it.
  • Avoid using brute force and do not overtighten the ratchet handle. This way, you won’t damage the threads on the engine block or break the plug.

Tips On How To Avoid Breaking The Plug Or Damaging The Threads On The Engine Block

Breaking the spark plug or damaging the threads on the engine block can be a nightmare, and the good news is that it’s quite easy to avoid these issues. Here are some tips to keep in mind:

  • Always use the correct-sized socket and ratchet to avoid damaging the plug or the engine threads.
  • Turn the ratchet gently and avoid using extreme force. Be patient, especially if the plug is old or rusty.
  • Clean the area around the plug before and after removing it. This will help prevent debris and dirt from falling into the engine cylinder.
  • Once you remove the spark plug, check it for any issues such as cracks, damage, or excessive wear. If needed, replace it with a new one.

By following these simple steps and tips, you can safely remove your lawn mower spark plug and avoid unnecessary damage to the engine block or the plug itself.

Step 3: Inspecting The Spark Plug

Explanation Of What To Look Out For When Inspecting The Spark Plug:

Inspecting the spark plug is a critical step in maintaining your lawn mower’s performance. A spark plug provides the initial source of electricity to ignite your lawn mower’s engine. If the spark plug is faulty, it can cause significant damage, as well as a decline in your lawn mower’s performance.

Here are some key things to keep in mind when inspecting your spark plug.

• make sure the engine is cool before removing the spark plug to avoid any injuries.

• examine the spark plug for indications of damage or wear, such as cracks, bending, or chipping.

• look for any signs of discoloration on the spark plug tip. A black oily remain indicates that the spark plug is dirty.

• check whether there are any deposits or corrosion evident on the metal shell of the spark plug.

In addition, don’t forget to read: How to Sharpen Lawn Mower Blades Without Removing

Tips On How To Differentiate Between A Fouled, Worn-Out, Or Damaged Spark Plug:

It’s essential to be able to distinguish between foul, worn-out, or damaged spark plugs. Each issue requires a different resolution, and the wrong diagnosis can cause further damage. Here are some tips to help you spot the differences:

• a fouled spark plug typically has black oily residue covering the plug’s end. This layer results in poor engine performance through a weak spark.

• a damaged spark plug has visual cracks that cause short circuits. This can cause extensive damage to your lawn mower’s engine, loss of power, and reduced fuel efficiency.

• a worn-out spark plug’s tip may appear worn down, which would result in difficulty starting your engine.

Importance Of Checking The Spark Plug Gap:

The spark plug gap directs to the distance between the center and ground electrodes. It’s imperative to verify the correct spark plug gap before installing the spark plug. Here’s why:

• an incorrect spark plug gap can cause an inconsistent burn of fuel, leading to erratic engine performance, incomplete combustion, misfire, and starting problems.

• a narrower gap than needed can increase the risk of a combustion event or potentially damage the spark plug.

• a wider gap than needed can cause your spark plug to misfire or experience difficulty starting.

With these tips, you can easily inspect your lawn mower’s spark plug and know when it’s time to replace it. Your lawn mower will thank you for keeping your spark plug in optimal condition, and you’ll enjoy a smoother and more efficient lawn mowing experience.

Step 4: Replacing The Spark Plug

Now that you’ve successfully removed the old spark plug, it’s time to install a new one. Here are some tips to help you do it right:

Explanation Of How To Properly Gap A New Spark Plug

A spark plug that has an incorrect gap can negatively affect the engine’s performance. Here’s how you can properly gap a new spark plug:

  • First, check the owner’s manual or the shop manual to decide the correct gap for your vehicle’s spark plug.
  • Use a spark plug gap tool to check the gap of the new spark plug and compare it to the gap instructed in the manual.
  • Use a gap gauge to adjust the gap to the correct measurement. Be gentle when bending the ground electrode to avoid damage.

Tips On Applying Anti-Seize Compound To New Spark Plugs

Applying an anti-seize compound to the new spark plug can make it easier to remove in the future and help to prevent it from seizing due to high heat and pressure. Here are some tips:

  • Apply a small amount of anti-seize compound to the threads of the new spark plug. Be careful not to get any on the electrode or porcelain insulator.
  • Spread the compound on the threads evenly with your finger or a small brush, making sure not to overcoat them.
  • Tighten the spark plug to the instructed torque specification listed in the manual.

How To Carefully Thread The New Plug Into The Engine Block

Here are the steps for threading the new plug into the engine block:

  • Make sure that the spark plug threads are clean and free of debris.
  • Carefully thread the new spark plug by hand into the engine block, being sure not to cross-thread or overtighten.
  • Use a torque wrench to tighten the spark plug to the recommended specification listed in the manual.
  • Double-check that the gap spacing is correct before installing the ignition wire.

Congrats, you’ve successfully replaced your spark plug and can now confidently get back to maintaining your lawn mower!

Step 5: Post-Replacement Maintenance

Now that you have replaced the spark plug successfully, it is time to move on to the reinstallation of the spark plug wire. Follow these steps carefully to provide your lawn mower runs smoothly:

Reinstallation Of The Spark Plug Wire

  • Grasp the spark plug wire firmly and push it onto the spark plug. You should hear a distinct click when the wire is properly seated.
  • Give the wire a gentle tug to confirm that it is secure.

Explanation Of How To Properly Torque The Spark Plug

  • Use a torque wrench to tighten the spark plug to the manufacturer’s specifications. Stay within the recommended torque range to prevent damage to the engine or spark plug.
  • If you don’t have a torque wrench, turn the spark plug clockwise by hand until it is snug, then give it a quarter turn with a wrench.

Read also: How to Change Oil in Lawn Mower?

Tips On How To Check For Proper Ignition After Spark Plug Replacement

  • Reconnect the spark plug wire and start the engine.
  • Listen for a smooth, even idle. If the engine is stuttering or misfiring, there may be an issue with the spark plug or the wire.
  • Check the spark plug sometimes to ensure that it isn’t fouled with oil or debris. If it is, clean it or replace it promptly.

By following these post-replacement maintenance steps, you can keep your lawn mower in top condition and ensure it runs efficiently and effectively.

Frequently Asked Questions For How To Remove Lawn Mower Spark Plug

How Do I Remove A Lawn Mower Spark Plug?

To remove a lawn mower spark plug, first disconnect the spark plug wire. Then, use a spark plug wrench to loosen and remove the spark plug. Carefully check the spark plug to decide if it needs to be cleaned or replaced.

Why Is It Important To Remove A Lawn Mower Spark Plug?

It’s important to remove a lawn mower spark plug for maintenance purposes. Over time, spark plugs become dirty and rusty and can cause problems with your lawn mower’s performance. Regularly inspecting and replacing spark plugs can help keep your mower running smoothly.

Can I Remove A Lawn Mower Spark Plug Without A Wrench?

While it’s not suggested, you can remove a lawn mower spark plug without a wrench. Take care not to damage the spark plug boot or wire in the process. Also, ensure that you do not round off the hex head on the spark plug by using the wrong-sized tool.

How Often Should I Replace My Lawn Mower Spark Plug?

It’s recommended that you replace your lawn mower spark plug every 100 hours of use or once per season. If you see any signs of wear and tear or if your mower is not running smoothly, then replacing the spark plug may be necessary even if it hasn’t been 100 hours.

What Size Spark Plug Socket Do I Need For A Lawn Mower?

The size of the spark plug socket you need for a lawn mower can vary based on your specific model. Many lawn mower spark plugs use a 5/8-inch socket. It’s recommended that you consult your owner’s manual or a professional before choosing a socket to ensure the right fit.


Changing a spark plug in your lawn mower is an easy task that you can perform on your own. As we have discussed, you need to identify the type of plug that can be used for your lawn mower, remove the old one, clean the area, and put in the new plugin.

Remember not to over-tighten the new spark plug. Repeat the process after several months and keep in mind the recommended spark plug changing intervals. By performing these regular maintenance tasks, you can extend the life of your lawn mower and enjoy a healthy, green lawn.

So, keep the tips we’ve covered here in mind, and don’t forget to always prioritize the safety measures before you start replacing the spark plug of your lawn mower. Happy mowing and stay safe!


  • David Mark

    David Mark is an experienced gardening guide with over 20 years of experience. He is passionate about helping people learn about gardening and creating beautiful, healthy gardens. David's love of gardening began at a young age, when he would help his parents in their backyard garden. He quickly learned the basics of gardening, and as he grew older, he began to experiment with different plants and techniques. After graduating from college, David worked as a landscaper for several years. This gave him the opportunity to work on a variety of different gardens, from small backyards to large commercial properties. He also learned how to install irrigation systems, build raised beds, and create patios and walkways. In 2005, David decided to start his own gardening website. He quickly became known for his expertise and friendly personality. He has helped hundreds of people create beautiful gardens, and he is always happy to share his knowledge with others. David is a certified Master Gardener, and he is a member of the American Society of Landscape Architects. He is also a regular contributor to gardening magazines and websites.

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