Why is My Mower Not Starting or Running Properly?

Key Takeaways

A lawn mower that won’t start often has a simple issue with its fuel, spark plug, or air filter.
Always disconnect the spark plug before you begin any troubleshooting or repairs on your mower.
If simple troubleshooting doesn’t work, bring your mower to the experts at Catoe’s Power Equipment to avoid causing more damage.

There’s nothing more frustrating than a lawn mower that won’t start when you’re ready to get the job done. The most common reasons why your lawn mower isn’t starting are simple issues with the fuel, air filter, or spark plug. A mower engine needs a good mix of gas and air, ignited by a strong spark, to fire up. When any of these are not working right, your mower will struggle or fail to start.

Why Won’t My Lawn Mower Start?

Most of the time, the problem is something simple that you can fix yourself. Think of your mower like a car, it needs three main things to work: fuel, air, and a spark. If any of those are missing or not working right, your mower won’t start.

Bad Gas: Did you leave old gas in your mower over the winter? Gas can go bad after just a few months and turn gummy. This sticky stuff can clog up the fuel lines and stop the engine from getting the gas it needs.
Dirty Spark Plug: The spark plug is what creates the little spark to ignite the fuel and get the engine going. If it’s old, dirty, or covered in gunk, it can’t create a good spark.
Clogged Air Filter: Just like us, a mower needs to breathe! If the air filter is full of grass, dust, and dirt, the engine can’t get enough air to mix with the fuel, which keeps it from running.
Battery Problems: For mowers with an electric start (the ones you turn on with a key), the battery is a big deal. If the battery is old or hasn’t been charged, it won’t have the power to crank the engine.
The Carburetor is Clogged: The carburetor is a small but important part that mixes air and fuel together before they go into the engine. If it’s clogged with old gas residue, the right amount of fuel can’t get through.

How to Troubleshoot a Lawn Mower That Won’t Start

Before you start poking around, remember safety first! Always disconnect the spark plug wire from the spark plug before you do any work on the mower. This makes sure the engine can’t accidentally start.

Check the Gas: Is It Fresh?

This is the easiest thing to check first. Look at the gas in the tank. If it looks dark or smells sour, it’s probably old. Try draining the tank and adding fresh, clean fuel.

Inspect the Spark Plug

To check the spark plug, you’ll need to locate it, which is usually on the side of the engine. Use a spark plug wrench to carefully unscrew it. Once it’s out, look at the tip. Is it black, oily, or cracked? If it is, it’s time for a new one. A clean, new spark plug can make a huge difference.

Clean or Replace the Air Filter

The air filter is usually in a plastic case near the engine. Open the case and take the filter out. If it’s just a little dusty, you can try cleaning it. But if it’s really dirty and clogged, it’s best to just replace it. A new air filter is inexpensive and can fix a lot of starting problems.

What About the Battery?

For mowers with an electric start, check the battery. Is it connected securely? Is it charged? Many mowers have a battery that you need to charge up, especially if it’s been sitting for a while. If the terminals are dirty, you can try cleaning them.

A Note About the Carburetor

The carburetor is a little more complicated. If you’ve tried all the other steps and your mower still won’t start, the problem might be a clogged carburetor. While you can sometimes clean these yourself with a special spray, it’s often a job for a professional.

When to Seek Professional Repairs?

Sometimes, no matter what you try, your lawn mower just won’t start. That’s when it’s time to bring it to the experts. Trying to fix something you’re not sure about can sometimes cause even more problems and might even cost you more in the long run. A professional can quickly figure out what’s wrong and get your mower running again safely.

Here at Catoe’s Power Equipment, we’ve been helping folks near Columbia, SC, with their lawn care needs since 1983. We know a thing or two about what makes a mower tick! Our customers trust us to get the job done right.

“Had trouble with starting my zero turn mower and started a chat with Catoe’s. I was willing to bring it in, but they told me to check a few things and when I replaced a fuse, that did the trick. Not many businesses today will offer free advice, but they did and I will be using them now on for my maintenance needs.” – Carl E.

“Best in the business there staff knowledgeable and professional definitely recommend them for all ur lawn care needs.” – Mark B.

“Bought new lawn equipment for the lawn care business and they provided great service.” – Stephen W.

Frequently Asked Questions

Q1: Why is my lawn mower smoking?

A: If your mower is smoking, it could mean you’ve put too much oil in it or it’s a sign of a more serious engine problem. It’s best to get it checked out by a pro right away.

Q2: How often should I change my lawn mower’s oil?

A: You should change the oil at least once per mowing season, or about every 50 hours of use. This keeps the engine running smoothly.

Q3: What kind of gas should I use in my mower?

A: Most mowers use regular unleaded gasoline. It’s important to use fresh gas and avoid using gas with a lot of ethanol, as it can be bad for small engines over time.

Q4: Why is my lawn mower sputtering and not staying on?

A: This could be a few things, including a dirty air filter, a clogged fuel line, or a dirty carburetor. It might also be a sign of a more serious issue with the engine itself.

Q5: How do I prepare my mower for winter storage?

A: Before storing your mower for the winter, you should run it until it’s out of gas or use a fuel stabilizer to keep the gas fresh. You should also change the oil, clean the machine, and take out the battery to store it somewhere warm.

Q6: Why is my mower’s blade not spinning?

A: The blade might be stuck because of a clump of grass or other debris. It could also be a problem with the belt that turns the blade or a more serious issue with the engine. Always make sure the mower is off and the spark plug is disconnected before checking the blade.

Q7: Can I use old motor oil in my mower?

A: No, you should always use the correct type of fresh motor oil for your specific mower. Using the wrong kind or old oil can cause a lot of damage to the engine.

Why Choose Catoe’s Power Equipment?

We know how important a healthy lawn is to you, and that starts with a mower that’s ready to work. So if you’ve tried everything and your mower still won’t start, don’t give up!

At Catoe’s Power Equipment, we’re not just a store, we’re a team of experienced professionals who are passionate about what we do. We have over 125 years of combined experience in the outdoor power equipment industry, and we treat every customer like family. We’re the go-to experts for troubleshooting lawn mowers and won’t start issues for the Columbia, SC area. We have the parts you need, the knowledge to fix any problem, and the friendly service to get you back to work fast.

Don’t wait! Give us a call or stop by our store in Columbia, SC. We’re here to help you get your lawn mower running again!