How To Check, Clean & Change a Lawn Mower Spark Plug

Hey there, fellow mower wranglers! Today, we're tackling the crucial task of checking, cleaning & changing a lawn mower spark plug.

If you have ever faced a stubborn mower that just won't start? Yep, that spark plug might be giving you grief.

This guide covers the tools you'll need, steps you should consider, and taking the right precautions to check, clean, and change a mower spark plug.

Let's skip the small talk and get that spark plug out, shall we?

Removing and Installing Spark Plugs

Tools and Safety Precautions

No time for guesswork, folks. We're diving straight into the toolbox and gearing up for safety. Here's what you need to know.

Essential Gear: Tools for the Job

Grab your trusty socket wrench, a properly sized spark plug socket, gloves (because blisters are nobody's friend), and safety glasses (let's protect those peepers). This is your toolkit for success.

Safety First: Precautions Before You Dive In

Before we start turning wrenches, let's disconnect that spark plug wire.

Safety tip: make sure your engine's cooled down to avoid any unnecessary burns.

No shortcuts here – let's get down to business safely and effectively.

Accessing the Spark Plug

Let's go straight to the heart of the matter: getting to that spark plug. Here's how to access it like a pro.

Pinpointing the Spark Plug's Hideout

You won't need a treasure map for this one. The spark plug is located on the engine, just follow the spark plug wire to find it.

Clear any debris or clutter around the area. A clean workspace is your best friend here.

No Obstacles Allowed: Clearing the Path

Clear the stage, folks. Remove anything that stands between you and that spark plug.

We're talking leaves, dirt, or any other bits that might think they're in the way. Time to show 'em who's boss.

Removing the Spark Plug

Alright, let's get that spark plug out of its cozy home. Follow these steps, and you'll have it in your hands in no time.

Step-by-Step Spark Plug Liberation

  1. Slide that spark plug socket onto your socket wrench.
  2. Gently slide it onto the spark plug.
  3. Start turning counterclockwise. Slow and steady wins the race – no need to rush.
  4. Feel the plug loosen up? Keep turning until you can remove it by hand.

Remember, patience is key. Tug it out smoothly, and you'll avoid any unwanted surprises.

Checking the Spark Plug Condition

Time to play detective with that spark plug. Here's how to inspect its condition and determine if it's the culprit behind your mower's blues.

Checking the Spark Plug Condition

Eagle-Eyed Examination

  1. Electrode and Insulator Inspection: Take a good look at the business end of the plug – that's the electrode and ceramic insulator. Any wear, deposits, or signs of damage? If it's looking beat-up, it might be time for a change.
  2. Gap Measurement: Grab an inspection tool, like a feeler gauge. Check the spark plug gap – the space between the electrode and the insulator. Is it according to your mower's specs? If not, time to consider some adjustments.
  3. Fouling or Buildup: Notice any fouling? That's when deposits, carbon buildup, or oil residue decide to crash the party. It's like junk food for your mower. Clean it up or opt for a fresh plug if it's looking nasty.

Remember, a spark plug in tip-top shape means a happier mower. Keep your standards high and your spark plugs even higher.

Cleaning or Replacing the Spark Plug

Alright, it's decision time.

Depending on what you've uncovered during your spark plug inspection, you might need to give it a little TLC or go all in for a replacement.

Here's the lowdown.

The Clean-up Operation

  1. Fouled Spark Plug: If you spot fouling, it's like your spark plug's crying out for help. Remove the gunk using an appropriate solvent and a trusty wire brush. Scrub it gently until it's looking spick and span.
  2. Adjust the Gap: If the gap isn't up to snuff, use your feeler gauge to carefully adjust it. The right gap is crucial for your mower's performance, so don't skip this step.

When to Say Goodbye

  1. Beyond Repair: Sometimes, a spark plug is beyond redemption. If it's damaged or worn out beyond the point of no return, it's time to part ways.
  2. Opt for Replacement: Head to your local store and grab a new spark plug that matches your mower's specifications. Don't forget to check and adjust the gap before installing.
Worn Out Spark PLug From a Lawn Mower

Remember, your mower's performance hangs in the balance of this decision.

Choose wisely, and your lawn will thank you for it.

Applying Anti-Seize (If Necessary)

Alright, we're getting into some final touches here.

If you're dealing with an older mower or you want to ensure future spark plug removal goes smoothly, consider using anti-seize compound.

Here's the deal.

Anti-Seize 101

  1. The Purpose: Anti-seize is like the wingman for your spark plug threads. It prevents them from seizing up over time, making your life easier when it's time for the next spark plug swap.
  2. Application: Take a dab of anti-seize compound and apply a thin, even layer to the threads of your new spark plug. Don't go overboard – a little goes a long way.

Cautionary Note: If your new spark plug comes with a pre-applied coating, skip the anti-seize.

You don't want to overdo it and end up causing more trouble than you're solving.

With this extra step, you're adding a bit of future-proofing to your mower maintenance routine.

Ain't nothing wrong with making things easier down the road.

Installing the New Spark Plug

Alright, it's time to put that new spark plug to work.

Let's get it installed and make sure we're not causing any hiccups along the way.

Secure Fitment: Installation Guide

  1. Hand-Tightening: Begin by gently threading the new spark plug into the socket. Get it as snug as you can by hand, ensuring you're not cross-threading.
  2. Spark Plug Socket: Once you've got it hand-tight, grab that spark plug socket and slide it onto the wrench. Use it to give the plug a final, careful tightening – clockwise this time.

Steady Does It: Avoid Overtightening

Remember, we're not assembling a rocket here. Over-tightening can lead to damage, and that's the last thing you want.

Give it a firm but controlled turn – you'll feel when it's properly seated.

With the new plug in place, you're on the home stretch. Keep it steady, and your mower will be raring to go in no time.

Reconnecting Spark Plug Wire and Final Checks

Almost there, folks! Let's finish strong and get that mower back on its feet.

Here's what you need to do before firing things up.

Making the Connection: Spark Plug Wire

  1. Secure Reconnection: Don't leave your spark plug wire hanging. Push it back onto the spark plug until you hear or feel a click. That's the sound of a solid connection.
  2. Double-Check: Give it a gentle tug to make sure it's snugly in place. No one wants a loose wire causing trouble mid-mow.

Last-Minute Inspections

  1. Connections: Take a quick look around. Did you tighten everything back up? No stray tools lying around? Good to go? Excellent.
  2. Safety First: Ensure your safety gear is off, and everything's cleared from around the mower.
  3. Test Run: Give that engine a start. Does it purr like a contented kitten? If it sounds good and there's no funny business, you're in the clear.
Testing a Lawn Mower after Spark Plug Replacement and tune-up

With the final checks done, pat yourself on the back. You've handled this spark plug removal like a seasoned pro. Your mower owes you one!


You've reached the finish line, my friend. Changing a mower spark plug is no longer a mystery to you.

You've got the tools, the steps, and the know-how to keep your mower humming along.

The Takeaway: A Job Well Done

Just remember, a healthy spark plug is a happy engine.

Regular maintenance keeps the heart of your mower strong and ensures a smooth mowing experience every time.

So, go ahead and give yourself a well-deserved pat on the back. You've conquered this task like a champ.

Now get out there and let your mower do its thing – with a spark plug that's up for the challenge.

Happy mowing!