How To Clean A Lawn Mower Spark Plug? (In 6 Simple Steps)

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A properly functioning set of spark plugs is necessary for every gasoline engine to perform reliably. Keeping the plugs clean is critical for getting the most power out of your machine.

Starting your lawnmower engine may be difficult if the spark plug is dirty. If you face challenges starting your lawn mower, it’s time to clean the spark plug.

Cleaning your equipment regularly is the simplest method to keep it functioning well and save money. Knowing when it’s time to clean the spark plugs is also essential.

As a general rule, replace your spark plugs anytime they get old or filthy. But what if you can’t afford to replace them? A simple cleaning technique may be necessary to keep your automobile operating like new for another few thousand kilometers.

How to Clean a Spark Plug on a Lawn Mower: Step-By-Step Process

The following is a thorough description of how to clean a lawnmower’s spark plug. Some readers may already be familiar with small engines to get started with this quick list. Still, we expect that most readers will want more knowledge.

Step 1: Take Out Your Spark Plug

Take Out Your Spark Plug
Image Source: besthomegear

Cleaning a filthy spark plug in a lawn mower is a simple task, but removing the plug might be difficult. Pulling a lawn mower’s spark plug is straightforward with the right tools.

The first step is to remove the cable by unhooking the spark plug from its connection.

Remove the spark plug hood by squeezing and wriggling it with your fingers. Then, remove the spark plug by placing the socket on the spark plug’s base. You may detach the spark plug with your fingertips after it is free to spin.

Also Read:- What Spark Plug to Use for Lawn Mower?

Step 2: Examine the Spark Plug’s Functional End

Examine the Spark Plug's Functional End
Image Source: lawnmowerguru

If the first step went well and the spark plug was successfully removed from the engine, you should check it before continuing.

Examine the apex for damage, such as a lack of sparks, carbon soot accumulation, oil/gas moisture, burning, or a chipped or broken electrode.

Check the body of the spark plug to see whether the tip is unbroken and whether the threads on the sides are the typical tan or brown color.

The only necessary maintenance is to inspect the ceramic casing for cracks and the junction where the ignition cord connects.

Also Read:- How to Start a Lawn Mower with a Bad Starter?

Step 3: Spark Plugs With Resistors Should Have Their Resistance Tested

Spark Plugs With Resistors Should Have Their Resistance Tested
Image Source: bestpushmowers

When a spark has a resistor, the imprinted code will feature the letter R. instead of a zero-value measurement.

A resistance value will be in use. The spark plug is safe if the resistance is between 4 and 7 ohms. When either extreme is present, spark plug performance drops considerably.

Some plugs regularly record 9 ohms. However, the value is often given as the final number of the code, or 9.

Step 4: Clean the Endcap

Clean the Endcap
Image Source: besthomegear

You must clean the tip of your spark plug if it is dirty because of carbon buildup, oil, gas, rust, or any combination of the four. You can wash spark plugs by hand or with a workbench vice.

To begin, thoroughly saturate the tip of your spark plug with rubbing alcohol or brake cleaner. Brush the whole end of your spark plug once it gets moistened. A light fluid application and mild brushing will usually be enough to remove particulates.

After loosening everything, wipe out your spark plug with a cloth or paper towel and let it air dry. It won’t take long because rubbing alcohol and brake cleaner evaporates almost instantly.

Spark plugs work best when clean; the tip is the most crucial part since it is where the spark is.

An electrode is a tiny metal prong at the engine end of a spark plug. Clean the spark plug whenever it gets dirty to keep it in a proper working condition.

You can clean a spark plug in a variety of ways. Each has its advantages, but you may optimize them by combining them.

Using Sandpaper

220-grit sandpaper is necessary. Begin sanding the curved end of the electrode by putting a piece of sandpaper under it. If the metal gets tarnished over time, scrape it clean. Smooth the back down to bare metal using a back-and-forth motion with the sandpaper.

To Make Use of a File

By filing down the unclean parts, you may clean the spark plug. Slide the file between the spark plug and the electrode to clean every crevice. If any accumulation exists, file it away until the metal is bare.

Use a Wire Brush to Clean

A wire brush may be used to clean the spark plug threads. After you clean the oil and filth, it will be simple to reinstall. Scrub along the lines to remove most dirt, then switch to a different angle to finish.

You don’t have to have new clothes, but you should eliminate any noticeable dirt clumps. Gloves are necessary for this cleaning. You do not want to get jabbed by the wire brush.

Blowtorch Techniques

Prioritize security. When dealing with fire or hot metal, please use gloves to protect your hands. Because spark plugs become pretty hot, hold them with pliers rather than bare hands. Keep it distant from you with long pliers. Applying much pressure on the pliers damages the spark plug.

Light the spark plug and put it in the blowtorch flame. Spark plugs can withstand high temperatures, such as those in a running engine. Any remaining oil or gasoline residue on the plug will get devoured and incinerated by the flames. Flip the pin so that both ends are towards the fire.

Remove the spark plug from the flame and switch off the blowtorch when the electrode starts to glow red hot. Allow the spark plug to cool on a safe, fireproof surface.

Step 5: Adjust the Spark Plug Gap

Adjust the Spark Plug Gap
Image Source: mowersboy

Measure the gap after cleaning the spark plug’s end. It’s easy to learn how to set the gap on a lawn mower spark plug.

You only need the right tools to measure the distance between the spark plug electrode and the grounding piece.

You may replace the spark plug in the mower after ensuring that the space is suitable according to the handbook.

Step 6: Spark Plug Reinstallation

Spark Plug Reinstallation
Image Source: thrivingyard

Reinstalling a spark plug is the same as removing it but in the other direction. First, make sure the spark plug gets threaded correctly by hand. Then, tighten the spark plug with the socket wrench. If you over-tighten it, it will be tricky to remove later.

After inserting a spark plug into an engine cylinder, snap the protective cover back onto the plug’s terminal. You may now resume driving since you properly reconnected the ignition cord.


  • If you find oil in the plug wires while replacing spark plugs, you must clean the plug holes for it to work again.
  • Checking the spark plug wires is vital for cleaning or replacing the wire. If you detect any damaged wires, you must repair them immediately; otherwise, the issues will remain.


How can I clean the dirt from the spark plugs?

To clean a spark plug safely, use a wire brush or a spray-on plug cleaner developed for this ignition component. A robust knife may also help remove stubborn buildup.

When Does a Lawn Mower Spark Plug Go Bad?

One sign is the color of the spark plug. If anything is black, sooty, or covered with carbon deposits, it’s time to replace it.

You can also examine the spark plug electrode to evaluate its condition. If rust or damage has occurred, it must get replaced. As a final option, clean the spark plug with a wire brush and some solvent.
You should replace it if cleaning does not enhance its look.

Is it feasible to clean and reuse a filthy spark plug?

Clean spark plugs can get reused, but only under specified circumstances. It should get replaced if the porcelain plug has any chips or fractures.

Second, remove any accumulated carbon from the electrode and its tip. After the carbon gets removed, the electrode must be appropriately gapped before the connection gets reconnected. Using a wire brush may be possible, but be careful not to harm the metal.

Can you clean spark plugs?

Yes, spark plugs can get cleaned, but the effort is typically not worth it. We cannot support this for several reasons. Finally, in terms of performance, a cleaned plug cannot compete with a fresh new one. Sharp corners are excellent conductors of electricity.

Can I clean Spark plugs with brake cleaner?

Yes. Apply brake cleaner to the plug and threads, then wipe away any excess filth with a clean cloth. Use brake cleaner and a wire brush to remove tough dirt deposits from spark plugs.


Sparkplugs being the essential component of a lawn mower, needs adequate maintenance. If your lawn mower is not starting or is in poor condition, then the reason could be dirt. Clean it by following the step-by-step guide mentioned in this article and  your lawn mower will be ready for its efficient use again.

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