Where is Your Lawn Mower Spark Plug? Answered

As an Amazon Associate, this site earns commissions from qualifying purchases. For more information click here.

The spark plug on your lawn mower produces the spark required to ignite the fuel mixture, so obviously it is important. But where is it located exactly? Spark plugs get worn out or damaged, so you have to replace it eventually. Knowing where to find the spark plug on your mower is therefore a must. You are in the right place as w will show where these plugs are found.

Spark plugs on push and rider lawn mowers are usually found on the back or side of the engine. Some Craftsman mowers have the spark plug at the front of the engine, while on Toro models it is on the side. The owner’s manual will specify its exact location.

How to Find Your Lawn Mower Spark Plug

The assist way to find the spark plug is to consult your lawn mower user guide. You can also check the back or side of the engine. Look for a short, thick wire connected to a cylinder on the engine.

Here is a quick guide to where most lawn mower spark plugs are found. Keep in mind this are only a general guideline, as your mower design may have implanted a different setup.

Lawn Mower TypeSpark Plug Location on the Engine
Push / walk behind lawn mowerBack or side
Rider and tractor mowerBack or side
Ariens Zero turn mowerOn the back
Toro riderThe right side
Briggs and Stratton On the front
Troy Bilt rider On the front
Cub Cadet riderOn the front
Husqvarna push mowerCenter and front
Husqvarna tractor Left side
Craftsman On the front and center

Note: the exact location of your lawn mower spark plug may differ. Check your owner’s manual.

Walk Behind Mower Spark Plug Location

With few exceptions, most spark plugs on push lawn mowers are on either side of the engine. One side is plugged into the engine cylinder and the other is connected to the wire. This end is also covered in a hood. No matter what type of lawn mower you have, the spark plug will always be connected to the engine.

Rider Mower Spark Plug Location

If you look at the table above, you will notice that many rider mowers have the spark plug at the sides. There are exceptions of course. When you do find it, the configuration is similar to that on a walk behind mower. The spark plug is connected to the wire and the cylinder.

One thing to keep in mind about rider mowers and tractors is that the engine may be located in the front or back. Regardless, when you do find the engine you will see the spark plug there.

When searching for the spark plug on rider mowers and tractors, you have to lift the engine cover first. Next check if the engine is on the front or the rear. Once you have figured that part, lift the cover.

You will find the spark plug and its hood on the engine. If the manual does not say specifically where it is located, look for a short wire plugged into a cylinder.

How to Identify a Lawn Mower Spark Plug

Knowing what a spark plug looks like makes it easier to find it. In most cases this is easy. In others it can be challenging because it under the engine cover. This is usually true for rider and lawn tractors. Even if you lift the engine cover, you have to know what a spark plug looks like.

Left, worn out spark plug. Right: new spark plug

This is what a lawn mower spark plug looks like. On the left is a worn out plug, on the right is brand new. Even with a hood, the spark plug is easy to identify. Spark plug wires are always visible as it is connected to the engine. While the locations vary depending on the manufacturer, once you see one spark plug it is similar to the others.

The spark plug wire is about 1/4 inch (1 cm) thick and quite short. A hood covers the spark plug, a piece of plastic that conceals the main body and its terminal.

If you are going to inspect the spark plug on your mower, it is a good idea to check the rest, including the bagger if it needs replacement.

Does My Lawn Mower Need a New Spark Plug?

If your lawn mower refuses start or it stalls, the spark plug may need to be replaced. In this section we will take a look at the most common symptoms and if it needs replacing.

The lawn mower engine does not start. This is the most obvious sign. Granted there are many reasons why a mower engine might refuse to run. But the first place to check is the spark plug. Remember that this component is needed to ignite the fuel. Without this there will be no combustion.

Greater fuel consumption. If the spark plug is fault, a good portion of the fuel will not burn. This means less fuel available for the engine. So you end up putting more fuel for the same amount of work that you do. If this happens, it could be an indication of a broken spark plug.

Poor performance and not idling. A worn out spark plug produces a snowball effect when it comes to performance. Because the engine does not have enough fuel, it cannot run as efficiently as it needs to. This results in poor grass cutting. The lack of fuel also affects idling.

A slowdown in cutting or unusual engine sounds can often be attributed to a damaged or worn out spark plug. So chalk this up to another symptom to look out for.

Mower does not respond to the pull cord. Pulling normally starts the engine, but if it does not work there could an issue with the spark plug. It comes back to the lack of fuel available.

Should You Replace or Clean a Lawn Mower Spark Plug?

If the spark plug electrodes are still intact, it might still be usable and just needs cleaning. If the electrodes are worn out, there is oil all over it or cracks, it is time to get a new spark plug.

Though only way to find out is to check the spark plug. These steps show you how it is done.

Step 1

Find the spark plug. Use the table provided earlier or check your owner’s manual.

Step 2

When you find the spark plug, remove the hood covering it. Next, get a spark plug socket and slide it into the plug. Rotate the socket until the spark plug comes loose.

Step 3

Hold the spark plug in your hand and examine it. If the electrodes are cracked, there is black carbon or oil over it, or looks worn, replace it with a new one.

If all you see is carbon buildup or oil, and the electrodes look fine, cleaning may suffice. Use a wire brush and soft cloth to wipe it off. Note that if oil is on the spark plug, it means there is an oil leak in your lawn mower. Check this guide on spark plugs leaking oil.

If the electrodes are damaged, buy a new spark plug. Once you have a new one, install it the reverse order you took out the old. Put it on and this time rotate it the other way around until it is a tight fit. Make sure to reconnect the wiring the same way.

If you need to buy a spark plug for your lawn mower, it has to be the exact match. Using the wrong type can damage the engine.

This can be prevented easily though. All you have to do is go online to the lawn mower manufacturer site. Enter your mower make and model and you will see what spark plugs are compatible with it.

You can also search for spark plugs on their official site and the product description will tell you if it is compatible with your mower. Another option is to go to a hardware store, show them the spark plug and they will find the right replacement.