The roar of a lawnmower is a familiar sound in summer, but what happens when that roar turns into a sputtering cough? One of the most common culprits for a lawnmower that won’t start is a faulty spark plug. But fear not! Changing a spark plug is a relatively simple task that even a novice DIYer can tackle. This comprehensive guide will walk you through the entire process, from identifying the spark plug to installing a new one.
The first step is to identify the spark plug. It’s usually located on the engine’s cylinder head, often under a wire cover. Once you’ve found it, you’ll need a spark plug socket wrench to remove it. Before installing the new spark plug, it’s important to gap it properly according to the manufacturer’s specifications. Finally, tighten the new spark plug to the proper torque, being careful not to overtighten.
Identifying Your Spark Plug: The First Step
Before you start taking anything apart, you need to know what you’re looking for. Finding the spark plug on your lawnmower is the first step, and it’s surprisingly easy.
The Telltale Signs
The spark plug is typically located on the top of the engine, often near the air filter housing. You’ll be able to identify it by its unique appearance:
- The Spark Plug Wire: A thick wire will be connected to the spark plug. This wire carries the electrical current that ignites the fuel in the engine.
- The Spark Plug Cover: The spark plug may be covered by a metal or plastic boot, which protects it from dirt and debris.
Finding the Spark Plug: A Quick Search
Once you’ve identified the spark plug wire, simply follow it back to its source. This will lead you to the spark plug itself.
Safety Note: Before you start working on your lawnmower, be sure to disconnect the spark plug wire to prevent accidental starting.
Gathering Your Tools: Essential Equipment
To change a spark plug, you’ll need a few basic tools. These tools can be found at any hardware store:
- Spark Plug Socket Wrench: This tool fits over the spark plug and allows you to loosen and tighten it. Choose the correct size for your spark plug.
- Wrench or Socket: You may need a wrench or socket to remove the spark plug cover if it’s present.
- New Spark Plug: Purchase a new spark plug that’s compatible with your lawnmower model. Refer to your owner’s manual for the correct type.
- Gap Gauge: This tool measures the gap between the spark plug’s electrodes. This gap needs to be adjusted for optimal performance.
- Work Gloves: Protect your hands while working on your lawnmower.
Disconnecting the Spark Plug Wire: Ensuring Safety
Before attempting to remove the spark plug, it’s crucial to disconnect the spark plug wire. This is a safety precaution that prevents any accidental starting while you’re working on the engine.
Disconnect the Wire with Care
- Locate the Spark Plug Wire: Find the thick wire connected to the spark plug.
- Pull the Boot Off: Gently pull the boot off the spark plug. Avoid pulling on the wire itself.
- Secure the Wire: Keep the spark plug wire safely out of the way to prevent it from coming into contact with any metal parts.
Removing the Old Spark Plug: Getting Ready for the New
Now that the spark plug wire is disconnected, you can safely remove the old spark plug.
Using the Socket Wrench
- Fit the Socket Wrench: Place the spark plug socket wrench over the spark plug. Ensure it’s securely attached.
- Loosen the Spark Plug: Slowly turn the wrench counterclockwise to loosen the spark plug. You may need to apply some force, but avoid using excessive force to prevent damaging the spark plug or the engine threads.
- Remove the Spark Plug: Once the spark plug is loose, carefully pull it out of the cylinder head.
Inspecting the Old Spark Plug: Checking for Signs of Wear
Now that you’ve removed the old spark plug, take a moment to inspect it. This will give you an idea of why your lawnmower wasn’t running properly and help you determine if the new spark plug is necessary.
Look for Common Issues
- Electrode Wear: The electrodes on the spark plug should be sharp and well-defined. If they’re worn down or rounded, it’s time for a new spark plug.
- Carbon Build-up: A buildup of carbon deposits on the spark plug can hinder its performance. If you see excessive carbon, you may need to clean it or replace it.
- Cracks or Damage: Check the spark plug for any cracks or damage. If you see any, it’s essential to replace the spark plug.
Gapping the New Spark Plug: Essential for Optimal Performance
Before installing the new spark plug, you need to ensure it’s gapped correctly. The gap between the spark plug electrodes determines the distance the spark needs to jump, and this gap needs to be precise for optimal performance.
Using a Gap Gauge
- Check the Manual: Refer to your lawnmower’s owner’s manual to determine the correct spark plug gap. This information will also be printed on the new spark plug’s packaging.
- Measure the Gap: Use a gap gauge to measure the gap between the electrodes.
- Adjust the Gap: If the gap isn’t correct, gently bend the side electrode to adjust it.
Installing the New Spark Plug: A Precise Procedure
With the new spark plug gapped correctly, you’re ready to install it. This process is similar to removing the old one, but in reverse.
Tighten the Spark Plug to Spec
- Thread the Spark Plug: Carefully thread the new spark plug into the cylinder head. Make sure the threads are aligned properly.
- Tighten with the Wrench: Use the spark plug socket wrench to tighten the spark plug. Avoid overtightening, as this can damage the spark plug or the threads in the cylinder head.
- Check the Torque: If you have a torque wrench, use it to tighten the spark plug to the specified torque.
- Reconnect the Spark Plug Wire: Carefully connect the spark plug wire to the new spark plug. Ensure a secure connection.
Starting Your Lawn Mower: A Test Drive
Now it’s time to see if your efforts have paid off!
Start Your Engine
- Connect the Battery: If your lawnmower has a battery, make sure it’s connected.
- Start the Engine: Follow the usual starting procedure for your lawnmower.
If the engine starts smoothly and runs without any issues, congratulations! You’ve successfully changed your spark plug. If you’re still having trouble, double-check that you’ve followed all the steps correctly.
Troubleshooting: Common Issues and Solutions
If your lawnmower still isn’t running after changing the spark plug, there are a few other potential issues you can check.
Common Problems
- Fuel Issues: Ensure your fuel tank is full and that you’re using fresh fuel.
- Air Filter Clogging: A dirty or clogged air filter can restrict airflow and prevent the engine from starting. Clean or replace the air filter.
- Carburetor Issues: A dirty or malfunctioning carburetor can cause problems with fuel delivery. Cleaning or rebuilding the carburetor may be necessary.
- Ignition Problems: If the engine is getting spark but not starting, there may be a problem with the ignition system, such as a faulty ignition coil or a broken ignition wire.
Maintenance Tips: Keeping Your Lawn Mower in Tip-Top Shape
While changing the spark plug is an essential maintenance task, other steps can help keep your lawnmower running smoothly.
Regular Maintenance for Longevity
- Clean Air Filter: Regularly clean or replace the air filter to ensure proper airflow.
- Change the Oil: Follow your lawnmower’s owner’s manual for recommended oil change intervals.
- Inspect the Fuel Lines: Check for leaks or cracks in the fuel lines.
- Clean the Carburetor: Clean the carburetor periodically to prevent fuel build-up.
By following these tips, you can keep your lawnmower running smoothly and reliably for years to come.
Conclusion: The Power of a Spark
A faulty spark plug can be a major inconvenience, but changing one is a simple maintenance task that can save you time, money, and frustration. By following the steps outlined in this guide, you can tackle this task with confidence and get your lawnmower running smoothly again. Remember to perform regular maintenance on your lawnmower to ensure it continues to perform at its best. With a little care, your lawnmower will be ready to tackle your lawn for many summers to come!
FAQ
What tools do I need to change a spark plug?
You’ll need a few basic tools to change a spark plug on your lawn mower. These include a socket wrench that fits the spark plug size, a spark plug gap tool, a wire brush, and possibly a torque wrench. Make sure you have the correct size socket wrench for your spark plug, and a gap tool that’s compatible with your new spark plug. You may also need a pair of pliers to help you remove the spark plug wire.
How do I know when to replace my spark plug?
There are a few signs that indicate your lawn mower’s spark plug needs to be replaced. If your mower starts hard, runs poorly, or misfires, the spark plug might be worn out. You can also check the spark plug itself for signs of wear, such as a burnt or corroded electrode. If you’re not sure, it’s best to err on the side of caution and replace the spark plug.
What type of spark plug should I use?
The type of spark plug you need for your lawn mower will be specified in your owner’s manual. Pay attention to the spark plug’s heat range, thread size, and length. It’s also important to use a spark plug that’s compatible with your mower’s ignition system. If you’re unsure, you can always consult with a local lawn mower repair shop.
How do I check the spark plug gap?
To check the spark plug gap, you’ll need a spark plug gap tool. Insert the tool between the spark plug’s center electrode and the ground electrode. The tool will indicate the current gap, which you can then adjust using a small screwdriver. Refer to your owner’s manual or the spark plug packaging for the recommended gap.
Should I clean my spark plug before reinstalling it?
While it’s not strictly necessary, cleaning your spark plug before reinstalling it can help improve its performance. You can clean the spark plug using a wire brush, making sure to remove any carbon deposits or other debris from the electrodes. Be gentle to avoid damaging the electrodes.
How tight should I tighten the spark plug?
Tightening the spark plug too tightly can damage the spark plug and cylinder head, while tightening it too loosely can cause leaks and performance issues. To avoid this, use a torque wrench to tighten the spark plug to the specified torque setting, which is usually listed in your owner’s manual.
What should I do if my lawn mower still won’t start after replacing the spark plug?
If your lawn mower still won’t start after replacing the spark plug, there could be other issues causing the problem. Check for fuel, spark, and compression. Make sure the fuel line is clear, the fuel filter is clean, and the carburetor is functioning properly. You can also check the ignition coil and the starter. If you can’t identify the problem, it’s best to consult with a lawn mower repair specialist.