A well-maintained lawn mower is the key to a lush, healthy lawn. While regular oil changes and blade sharpening are essential, one often-overlooked component that significantly impacts your mower’s performance is the spark plug. This small but mighty part ignites the fuel-air mixture, bringing your mower to life. A worn-out or fouled spark plug can lead to a host of problems, from sputtering and stalling to reduced power and poor fuel efficiency. Knowing how to change spark plugs yourself is a valuable skill that can save you time and money. It’s a relatively simple task that can be accomplished with basic tools and a little know-how.
Understanding Spark Plugs
Spark plugs are designed to withstand extreme heat and pressure. They consist of a central electrode, a ground electrode, an insulator, and a threaded base that screws into the engine’s cylinder head. The spark plug creates a high-voltage electrical spark between the electrodes, igniting the compressed fuel-air mixture in the combustion chamber. Over time, the electrodes can wear down, the insulator can become fouled with carbon deposits, or the gap between the electrodes can widen, all of which can hinder the spark’s ability to ignite the fuel-air mixture effectively.
Signs of a Worn-Out Spark Plug
Recognizing the signs of a worn-out spark plug can help you avoid potential engine problems. Here are some common indicators:
- Difficulty starting the mower
- Engine sputtering or misfiring
- Loss of power
- Rough idling
- Decreased fuel efficiency
- Black or oily deposits on the spark plug
Gathering the Necessary Tools and Materials
Before you begin changing your spark plugs, ensure you have the right tools and materials. Having everything on hand will make the process smoother and more efficient.
Tools
- Socket wrench set
- Spark plug socket (usually 5/8″ or 13/16″)
- Torque wrench (optional but recommended)
- Gap gauge
- Wire brush or compressed air
- Safety glasses
- Work gloves
Materials
- New spark plugs (check your owner’s manual for the correct type and gap)
- Anti-seize compound (optional but recommended)
Preparing Your Lawn Mower
Safety should always be your top priority when working on any machinery. Disconnect the spark plug wire before starting any work on the engine.
Safety Precautions
- Wear safety glasses to protect your eyes from debris.
- Wear work gloves to protect your hands from sharp edges and hot surfaces.
- Ensure the lawn mower is on a level surface and the parking brake is engaged.
- Never work on a hot engine. Allow the engine to cool completely before starting any maintenance.
Locating the Spark Plugs
The location of the spark plugs varies depending on the make and model of your lawn mower. Consult your owner’s manual for the specific location on your mower. Generally, spark plugs are located on the top or side of the engine, near the cylinder head. (See Also: Is Ngk A Good Spark Plug? The Verdict)
Removing the Old Spark Plugs
Once you’ve located the spark plugs, you can begin removing them. Use the spark plug socket and socket wrench to carefully loosen and remove the spark plugs. Avoid overtightening or cross-threading the spark plugs.
Inspecting the Old Spark Plugs
Take a moment to inspect the removed spark plugs. Look for signs of wear, such as eroded electrodes or a gap that is too wide. Also, check for carbon deposits or oil fouling, which can indicate engine problems.
Installing the New Spark Plugs
With the old spark plugs removed, it’s time to install the new ones. Before installing, ensure the new spark plugs are properly gapped according to the specifications in your owner’s manual. Use a gap gauge to adjust the gap if necessary.
Applying Anti-Seize Compound (Optional)
Applying a small amount of anti-seize compound to the threads of the new spark plugs can help prevent them from seizing in the engine. This can make future spark plug changes easier.
Tightening the Spark Plugs
Hand-tighten the new spark plugs until they are snug. Then, use the spark plug socket and socket wrench to tighten them further. If you have a torque wrench, use it to tighten the spark plugs to the manufacturer’s specified torque. Overtightening can damage the spark plug threads or the engine.
Final Steps and Testing
Once the new spark plugs are installed, reconnect the spark plug wires. Double-check all connections to ensure they are secure. Start the lawn mower and let it run for a few minutes to ensure the new spark plugs are firing properly. (See Also: What Size Are Lawn Mower Spark Plugs? Essential Replacement Guide)
Checking for Leaks
Inspect the area around the spark plugs for any signs of oil or fuel leaks. If you notice any leaks, tighten the spark plugs or replace the gaskets as needed.
Recap
Changing spark plugs is a relatively simple maintenance task that can significantly improve your lawn mower’s performance and longevity. By following these steps and using the right tools and materials, you can easily change your spark plugs yourself. Remember to always prioritize safety, consult your owner’s manual for specific instructions, and inspect the old spark plugs for any signs of engine problems. Regular spark plug changes, along with other essential maintenance tasks, will ensure your lawn mower runs smoothly for years to come.
Frequently Asked Questions
What is the recommended interval for changing spark plugs?
The recommended interval for changing spark plugs varies depending on the make and model of your lawn mower. However, a general guideline is to change them every 100 hours of use or annually, whichever comes first. Always consult your owner’s manual for the specific recommendations for your mower.
Can I use a regular socket wrench to remove and install spark plugs?
While you can technically use a regular socket wrench, it’s not the best tool for the job. A spark plug socket is specifically designed to fit spark plugs and has a rubber insert that helps prevent damage to the spark plug’s porcelain insulator. Using a regular socket wrench can increase the risk of damaging the spark plug.
What does it mean if my spark plug is fouled?
A fouled spark plug is coated with carbon deposits, oil, or other contaminants that prevent it from functioning properly. This can be caused by a variety of factors, such as a rich fuel mixture, oil leaks, or improper engine maintenance. If your spark plug is fouled, it needs to be cleaned or replaced. (See Also: What Do Fouled Spark Plugs Look Like? Signs Of Failure)
How do I know if my spark plug gap is correct?
The gap between the electrodes of a spark plug must be within a specific range to ensure proper ignition. Use a gap gauge to measure the gap and adjust it as needed. The correct gap is specified in your owner’s manual.
What type of anti-seize compound should I use on spark plugs?
Copper-based anti-seize compound is generally recommended for spark plugs. It provides good lubrication and corrosion resistance. Avoid using aluminum-based anti-seize compounds, as they can react with the aluminum components of the spark plug and engine.