How to Know If Mower Spark Plug is Bad

Is your lawn looking a little worse for wear? It might be time to think about replacing your mower spark plug.

Spark plugs are an essential part of any lawnmower, and if they start to go bad, they can cause all sorts of problems with your machine.

In this blog post, we’ll teach you how to know if your mower spark plug is bad – and how to replace it if it is. Keep reading to learn more.

What is a Spark Plug

A spark plug is a small device used to create a spark in the engine of a lawnmower. It is an essential part of the machine, and if it starts to go bad, it can cause all sorts of problems.

To know if your mower spark plug is bad, you’ll need to look at it and see if there are any signs of wear or damage. If there are, then it’s time to replace the plug.

Signs Mower Spark Plug is Bad

Checking a Mower Plug

If you need to know if your lawnmower spark plug is bad, the best thing to do would be to check it out yourself.

You can easily open up your mower and take a look at the spark plug right away. If you find that it is damaged or burned, then chances are that you will have to replace it.

If you are not sure if the plug is bad, you can always swap it out with another known good one. This will fix any problems that you are having with your mower.

How to Know if Mower Spark Plug is Bad- Signs

The signs of a bad mower spark plug are pretty simple, and you will be able to identify the problem right away. Some of these include:

1. Excessive Fuel Consumption

One of the main signs of having a bad spark plug is excessive fuel consumption. If your lawn mower is using more fuel than usual, it might be because the plug is not working correctly.

When the spark plug does not create a spark, it can cause the engine to run inefficiently. This will result in your lawnmower using more fuel than it should.

2. Poor Performance

If your lawnmower is not performing as well as it should, it might be because of a bad spark plug. When the plug is not working properly, it can cause the engine to run slowly or unevenly.

This will result in your lawnmower being unable to cut your grass correctly.

3. Engine Has Trouble Starting

Another sign that you have a bad spark plug is trouble starting the engine. If your mower is taking longer than usual to start, or if it just won’t start at all, it might be because of the plug.

When the spark plug is worn out, it can result in poor engine performance and difficulty in starting the lawnmower.

Also read: Riding mower sputters and backfires when trying to start

4. Unusual Smell

One of the last signs of having a bad spark plug is unusual smells. If your lawnmower starts to emit smoke, or if it emits a burning smell while running, then chances are that the plug has gone bad.

This will cause the engine to run inefficiently and may result in misfires. This can cause the engine to emit smoke or unusual smells.

Also read: Lawn mower oil extractor pumps

How to Replace a Mower Spark Plug

If you think that your mower’s spark plug might be bad, don’t worry – it’s a simple fix. All you need to do is remove the plug and replace it with a new one. Here are the steps:

  1. Shut off the engine and disconnect the spark plug lead from the ignition. You may have to unscrew the plug wire, but you will be able to remove it from the engine once you do this.
  2. Remove all of the old dirt and debris around your mower spark plug. Make sure that every bit of it is out of there before you go further with your project. Using a brush is an easy way to remove this dirt.
  3. Replace the spark plug with a new one of the same quality. You can buy these plugs at any hardware or big box store that sells lawnmower parts, and they are relatively inexpensive. Be sure to use your model number to get an exact match for your mower.
  4. Connect the spark plug lead back to its original location and reattach it to your mower. Turn on the engine and test out the new plug, ensuring that it is working properly.

FAQs : How to tell if spark plug is bad lawn mower

Will a Lawn Mower Start if the Spark Plug is Bad?

It might start, but chances are that it won’t. If the spark plug is not working properly, then your lawn mower will not run properly or efficiently.

This means you will have problems with your grass being cut evenly, poor performance while mowing, and trouble starting the engine.

Also read: Riding lawn mower lift jack

What Causes the Spark Plug to Fail?

Failures in the spark plug are often caused by dirt or debris. This can cause them to wear out or become clogged.

They may also not be installed appropriately, so they do not work as efficiently as they should.

How Often Should I Replace the Spark Plug on My Lawn Mower?

You should replace your lawnmower’s spark plug every year or two to ensure that it is in optimal condition.

This will also prevent it from failing, which can, in turn, cause your lawnmower to run inefficiently.

Can I Replace the Spark Plug Myself?

Yes, it is simple to replace your lawnmower’s spark plug yourself. All you need to do is remove the old one and replace it with a new one.

Be sure to check your owner’s manual for specifics on how to do this, as well as the correct model.

Mower spark plugs are an essential part of your lawnmower’s engine. They provide the power that starts and runs it, so when they stop working properly, you could have problems starting or running your mower.

Fortunately, replacing them is easy to do yourself, which means you can save money on expensive repairs. If this sounds like something you would be interested in doing more often than not for peace of mind and convenience, be sure to get a new one every year or two.


  • Ricky

    Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care.

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