Lawn Mower Won’t Stay Running: Possible Issues and Fixes

You’re mowing your lawn. Things are running smoothly, and you’re just about finished.

All of a sudden, your lawn mower comes to a stop.

You start it back up, and it shuts off no more than a minute later. Your lawn mower won't stay running. Why is that?

If your lawn mower won’t stay on, we might have the answers you’re looking for.

We’ll be taking a look at a few common issues that may cause your lawn mower to stop running repeatedly.

We will also list some troubleshooting tips you should be aware of in case you want to fix the issue yourself.

How Do You Fix a Lawn Mower That Won’t Stay Running?

Whether you operate a riding mower or a push mower, there will be times where your lawn mower will run one minute and stop running the next.

No matter how many times you start it up, it stops again. This becomes a consistent annoyance, and you obviously want to get it fixed.

Many issues can cause this to happen, and figuring out the real problem can be tough to do.

Before anything else, you would want to first inspect the lawn mower in its entirety.

With a thorough look through, you will be able to determine where the issue could be stemming from.

Don’t know where to start? Here’s a quick inspection guide:

1. Check the spark plug.

The spark plug plays a huge role in the ignition sequence. Without it, you will never be able to start the engine.

What you’ll want to do is inspect the spark plug itself. Is it dirty or littered with debris?

Try removing the spark plug, cleaning it off, and putting it back on. Then, attempt to start it again and see what happens.

The spark plug may even be damaged to a point where it can cause the lawn mower to start up briefly and stop soon after.

This will likely put you in a position where you’ll need to replace the spark plug outright.

2. Is the gas cap blocked?

Another thing to check to learn how to fix a lawn mower that won't stay running is the gas cap.

The gas cap is known for stabilizing air pressure inside the tank.

If the gas cap is obstructed, the airflow inside will be more vacuum-like.

As a result, the gas flow will be interrupted and will cause the carburetor to fail, so the lawn mower won't stay running for long.

Using a thin wire, you can clean the gas cap itself. However, if the cap has sustained damage, then plan on replacing it as soon as possible.

3. How much oil is in the reservoir?

Let’s say you have a clean carburetor.

If your lawn mower will not stay running, chances are there may be too much oil in the reservoir.

Another sign of this issue is when you see white smoke billowing from the engine.

To address this, stop using the lawn mower and store it at an upward angle. Have a heavy enough object hold down the handle.

The purpose of this is to allow the oil to run its course through the rest of the engine.

Keep the lawn mower in this position for about an hour, and try restarting it when you are ready.

At that point, you should be able to run it with no problems.

4. Carburetor Issues

More often than not, these “start and stall” issues on a lawn mower can be caused by one part—the carburetor.

One such issue is clogging in the carburetor bowl.

In most carburetors, there’s a small bowl underneath held together by a screw.

If the hole that holds the screw is clogged, it will cut off any airflow that the carburetor will need.

To unclog the bowl, you’ll want to remove the bowl screw using a ½-inch plug wrench and then clean the hole using a thin wire.

Lastly, use a carburetor cleaner to spray the hole.

Once you’re done, put the screw back and try not to over-tighten it.

If your lawn mower will not stay running, your carburetor may also be worn down to the point where it needs to be replaced.

Of course, the obvious troubleshooting tip we can give you in this situation is, well, just replace it.

Why Does My Lawn Mower Only Run for a Few Seconds Then Dies?

This is one of the reasons why maintaining your lawn mower on a regular basis is so important.

Unfortunately, this is what a huge percentage of lawn mower owners fail to do.

By performing regular maintenance, you’ll be able to catch problems early on and keep them from damaging your unit.

The issues mentioned earlier are a good starting point.

Then again, if your lawn mower runs for a few seconds and then quits suddenly, it could be a sign of a serious problem.

If this problem occurs, odds are you might want to check on the carburetor first.

As mentioned before, it’s the one part that will cause this issue the most. You’ll want to check for any signs of wear while cleaning it up.

While fixing the issue may be as simple as regular cleaning, the carburetor in your lawn mower won’t last forever.

The next best thing would be to replace it. The starting and stopping of your lawn mower may very well be an indicator.

Since your lawn mower’s engine needs fuel, the fuel line will need to be checked, too.

If there is enough gas running through there, you should be good to go. Otherwise, you would need to clean it.

Also, make sure you have enough gas inside the tank. Most (if not all) lawn mowers have a two-gallon tank.

Be sure to fill it up first before starting it up. Doing so will help you rule out the possibility of low fuel being the culprit.

If it starts and then dies on a full tank, check to see if the fuel line is obstructed.

As mentioned before, the gas cap may also be clogged, as well.

What Does It Mean When Your Lawn Mower Starts Then Stops?

When your lawn mower won’t stay on, this calls for a little bit of quality time in the garage to try and figure out what the problem is.

Again, you won’t know until you try out some of the troubleshooting tips we listed earlier.

When parts are worn down or already at the end of their lifespan, you may want to consider getting them replaced.

If you want to prevent your mower from starting or stopping, pay attention to some of the other signs of a part consistently failing.

Once again, let’s focus on the carburetor.

Even before the lawn mower starts and stops, you’ll want to focus on some of the other signs.

These include but are not limited to a poor fuel economy, your lawn mower may idle a lot quicker than usual, or if the engine just simply stalls.

When your lawn mower starts and stops, does this mean you have to replace the lawn mower itself?

Not always.

It could mean replacing the needed parts or even repairing the engine itself.

A simple parts replacement can lengthen the lifespan of a lawn mower.

With proper maintenance, the average lawn mower can last you anywhere from eight to 10 years.

That’s why you’ll want to keep it clean and do routine maintenance on it regularly.

Failure to perform any kind of maintenance can shorten its lifespan or that of its inner parts.

And, yes, that can lead to your mower starting up one second and dying the next.

How Do You Stop a Lawn Mower From Turning Off?

This should not be confused with stopping a lawn mower from turning off properly.

This pertains to preventing a lawn mower from shutting off by itself while you are in the middle of mowing your lawn.

Knowing how to fix a lawn mower that won't stay running will be key here.

Starting with a simple cleaning and maintenance routine should be the first thing.

After you have thoroughly cleaned everything, from the carburetor to the fuel system, you’ll want to test it out.

If the starting and stopping continue, your next best option would be replacing any parts that may be worn or defective.

Whether you’ve had the lawn mower for years or just bought it, these things can happen.

Most lawn mowers will have a warranty that the manufacturer will honor in the event of issues like this.

Lawn Mower Won't Stay Running: Final Thoughts

A lawn mower that won’t stay running can be a sign of some issues within the engine.

It’s better to keep it well maintained over time so that it doesn’t die on you sooner rather than later.

If and when you run into this specific situation, and you have kept it well maintained, it might be a sign that you’ll need to replace the parts soon.

Remember, the carburetor is one of your must-need parts for a lawn mower to start working.

Also, your spark plug may need to be cleaned regularly to prevent issues with the ignition process.