How to Clean & Replace Lawn Mower Spark Plugs

The spark plug is a key component of lawn mowers because it ignites the fuel-and-air combination inside the engine’s cylinder. They also help power millions of small engines, including mowers, tractors, snow blowers, chainsaws, and leaf blowers.

But the quality of the spark decreases as spark plugs become dirty or start to fail electrically, resulting in incomplete fuel combustion and decreased engine performance and efficiency.

This Lawn Advisors article will help you learn how to change, remove, and clean lawn mower spark plugs to keep your machines running smoothly.


Spark Plug Components

Spark Plug Components

A spark plug has four basic components:

1. A threaded metal shell or casing.

2. The output terminal of the ignition coil is connected to the central or live electrode by a wire that is well-insulated and usually contains a resistor.

3. An insulator to electrically isolate the outer shell from the central electrode. It stops high voltages from escaping from the electrodes.

4. An outer or ground electrode. It is also sometimes referred to as the side electrode.


How Lawn Mower Spark Plugs Work?

Spark plugs are a key component of lawn mowers because they ignite the fuel-and-air combination inside the engine’s cylinder. Every spark plug’s gap at the tip is jumped by high-voltage electricity at the appropriate time to start fuel burning. 

 The quality of the spark decreases as spark plugs become filthy or start to fail electrically, resulting in incomplete fuel combustion and decreased engine performance and efficiency. One of the most important maintenance procedures for a gas lawn mower’s performance is spark plug maintenance.


When to Check and Replace Lawn Mower Spark Plugs?

When to Check and Replace Lawn Mower Spark Plugs

You should check and/or replace spark plugs as part of the routine lawn mower and small engine maintenance.

– Once a season.

– Every 25 hours of use.

– If your lawn mower our outdoor power equipment won’t start.


How to Check a Fouled or Damaged Lawn Mower Spark Plugs?

1- Disconnect the spark plug lead. When you remove the spark plug, clean the area around it to prevent getting debris into the combustion chamber.

2- Using a spark plug socket, remove the spark plug.

3. Using a wire brush and plug cleaner spray, remove any light deposits from the plug.

4. Check the spark plug for very stubborn deposits, porcelain that has cracked, or electrodes that have been burned away. Replace the spark plug if any of these conditions exist.

5. Check the spark plug gap and make any necessary adjustments.

6. Replace the plug if it seems to be in working order, being careful not to overtighten (15 ft5 lbs MAXIMUM), and reattach the spark plug lead.

7. And you can now start the engine!

If the engine tries to turn over (even for a second) and stops, then you have a spark. This would indicate that the problem is likely located elsewhere (fuel, carburetor, valves, etc.). There can be a problem with your ignition system if the engine won’t even start. The spark plug should be changed first.

Here’s a valuable video showing you how to check, clean and replace lawn mower spark plug.


How to Clean Fouled Lawn Mower Spark Plugs?

How to Clean Fouled Lawn Mower Spark Plugs

Use a wire brush or spray-on plug cleaner specially designed for this ignition part to safely clean a spark plug. A sturdy knife can also be used to scrape off stubborn deposits.

And NEVER clean a spark plug with a shot blaster or abrasives!

Check out this video below to learn how to clean fouled lawn mower spark plugs properly.


Can Lawn Mower Spark Plugs Be Reused?

Though there’s a good reason not to, you can. Spark plugs can fail electrically in addition to producing that alternative electrical path thanks to oil and carbon deposits.

This is why a used plug that has been meticulously cleaned can still malfunction under load and fail to provide the best spark possible inside the engine.


Lawn Mower Spark Plugs FAQ


To Wrap Up

You now know everything related to lawn mower spark plug and how to clean and replace it.

If you have any questions about lawn mower spark plugs, leave them in Lawn Advisors comments box below and we’ll get back to you as soon as possible.

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