Why Does My Lawn Mower Start Then Die? Find Out Here


Do you have a lawn mower that starts but then dies shortly after? If this is the case, you’re probably wondering why it happens and what you can do about it.

In this article, we’ll explore some of the most common causes of a lawn mower starting then dying and offer some tips on how to troubleshoot the issue.

From dirty air filters and stale fuel mixes to spark plugs in need of replacement and malfunctioning carburetors, you’ll learn how to diagnose and potentially fix the problem so you can get back to mowing your lawn.

So let’s get started!

Short Answer

There are a few common reasons why a lawn mower might start, then die.

It could be due to a clogged air filter, which is restricting the air flow to the engine, or it could be that the spark plug is not working properly.

Additionally, the carburetor or fuel filter could be dirty or clogged, preventing fuel from reaching the engine.

Lastly, it could be a problem with the ignition switch or a lack of fuel in the tank.

Common Causes of a Lawn Mower That Starts Then Dies

If your lawn mower starts then dies shortly after, the cause could be due to a variety of issues.

The most common causes include a dirty air filter, a stale or old fuel mix, a spark plug in need of replacing, or a malfunctioning carburetor.

Other possible causes include clogged fuel lines, a faulty ignition switch, or a damaged muffler.

A dirty air filter can be one of the main culprits for a lawn mower that starts then dies.

When the air filter is clogged, it restricts the air flow to the engine, causing the engine to run too lean and eventually die.

To check if your air filter is clogged, remove it and hold it up to the light.

If you cannot see light through the filter, it is time to replace it.

A stale or old fuel mix can also be the cause of a lawn mower that starts then dies.

Gasoline degrades over time and can cause the engine to run improperly.

To prevent this, use fresh gasoline and mix it with oil according to the manufacturer’s instructions.

It is also important to use a fuel stabilizer to help extend the life of the fuel.

A spark plug in need of replacing can also be the cause of a lawn mower that starts then dies.

If the spark plug is not firing properly, it can cause the engine to misfire and eventually die.

To check if the spark plug is the cause, remove it and inspect it for signs of wear and tear.

If the spark plug appears corroded or is covered in soot, it is time to replace it.

If the carburetor is malfunctioning, it can also be the cause of a lawn mower that starts then dies.

A carburetor regulates the air and fuel mixture to the engine and if it is not working properly, it can cause the engine to run too lean and die.

To check if the carburetor is the cause, remove it and inspect it for signs of wear and tear.

If the carburetor appears damaged, it is time to replace it.

Clogged fuel lines can also be the cause of a lawn mower that starts then dies.

If the fuel lines are clogged, it can restrict the fuel flow to the engine, causing it to run too lean and eventually die.

To check if the fuel lines are clogged, remove the fuel filter and inspect the lines for clogs or blockages.

If the fuel lines are clogged, it is time to replace them.

A faulty ignition switch can also be the cause of a lawn mower that starts then dies.

If the ignition switch is not sending the correct signal to the engine, it can cause the engine to misfire and eventually die.

To check if the ignition switch is the cause, remove the switch and inspect it for signs of wear and tear.

If the ignition switch appears damaged, it is time to replace it.

Lastly, a damaged muffler can also be the cause of a lawn mower that starts then dies.

If the muffler is damaged, it can restrict the exhaust from the engine, causing it to run too lean and eventually die.

To check if the muffler is the cause, remove it and inspect it for signs of wear and tear.

If the muffler appears damaged, it is time to replace it.

If your lawn mower is experiencing this issue, it is best to have it looked at by a professional.

A professional can inspect the lawn mower and diagnose the issue, allowing them to repair it quickly and get your lawn mower up and running again.

Dirty Air Filter

When it comes to why your lawn mower might start then die, one of the most common causes is a dirty air filter.

The air filter is what allows the engine to take in air and mix it with the fuel.

If the air filter is clogged or dirty, this can affect the flow of air and cause the engine to misfire or stall.

To check the air filter, remove it from the mower and inspect it for any dirt or grime.

If the filter appears dirty, it should be replaced.

If it appears clean, it may be worth cleaning it with a damp cloth and a mild detergent.

Make sure to let it dry completely before reinstalling it.

Stale or Old Fuel Mix

When your lawn mower starts and then dies, a stale or old fuel mix could be the culprit.

This happens when the fuel mix has been sitting in the tank for too long, and the gasoline has become sludgy or has evaporated.

If youve been using the same fuel mix in your lawn mower for more than three months, its time to refresh it.

To do this, simply drain the old fuel mix from the tank and replace it with a fresh one.

Its also important to use a fuel mix with an ethanol content of no more than 10 percent.

Using a fuel mix with a higher ethanol content can cause your lawn mower to start and then die due to corrosion and deposits in the fuel system.

In addition, ethanol can cause your fuel to evaporate faster, which can leave you with stale fuel in the tank.

Its also a good idea to use a fuel stabilizer to ensure your fuel mix is as fresh and clean as possible.

Fuel stabilizers can help prevent the fuel from going bad, and they also help keep the fuel system clean.

To get the most out of your fuel stabilizer, be sure to add it to the tank before you fill it with fresh fuel.

Spark Plug in Need of Replacing

When it comes to why your lawn mower might start and then die, a faulty or worn-out spark plug could very well be the root cause.

A spark plug is the component responsible for igniting the engines fuel and air mix, so if its not working properly, the lawn mower wont start.

Spark plugs can become worn out over time, thus leading to their demise.

This can be due to age, wear and tear, or even corrosion.

If the spark plug isnt providing enough spark, then the lawn mower wont stay running for long.

To check if your spark plug is the culprit, you can use a spark plug tester to determine if the spark plug is working properly.

If the spark plug is determined to be faulty, then youll need to replace it.

You can purchase a replacement spark plug from your local hardware store or online.

When replacing the spark plug, make sure to use the correct type for your lawn mower.

Its also important to use the correct gap for the spark plug, as this will ensure that the spark plug will ignite the fuel and air mixture correctly.

If youre unsure of the gap, consult your lawn mowers manual for the correct information.

Once youve replaced the spark plug, make sure to double-check the gap and then reassemble the lawn mower.

If the spark plug was indeed the cause of your lawn mowers issue, then the lawn mower should start and stay running correctly.

Malfunctioning Carburetor

When it comes to lawn mowers, a malfunctioning carburetor is one of the most common causes of starting and then dying shortly afterwards.

A carburetor is responsible for mixing the air and fuel and delivering it to the engine.

If the carburetor is malfunctioning, it can cause the fuel to be delivered at an incorrect ratio, which can prevent the engine from running correctly.

Common signs of a malfunctioning carburetor include a strong and unpleasant smell of gasoline, a lack of power when the engine is running, and the engine dying shortly after starting.

To diagnose the issue, it is necessary to remove the carburetor from the engine and inspect it for any damage or faulty parts.

It is also important to check the fuel lines for any blockages or leaks.

In some cases, the carburetor can be repaired or adjusted to fix the issue.

However, it is often best to replace the carburetor entirely as it is a relatively inexpensive part and doing so can reduce the risk of further issues.

If you are unsure of how to diagnose and repair the issue, it is best to consult with a professional.

Other Potential Causes

Besides the most common causes, there are other potential causes for why your lawn mower starts then dies shortly after.

For instance, the fuel lines may be clogged, which can be caused by a build-up of dirt and debris, or a faulty ignition switch.

In some cases, a damaged muffler can also be the culprit, as it can cause the engine to not be able to produce enough power to keep the mower running.

If your mower is having any of these issues, it is best to have it looked at by a professional.

The fuel lines are an important part of the mower, as they ensure that the fuel is delivered correctly to the engine.

If the fuel lines are clogged, they can prevent the fuel from reaching the engine, resulting in the mower starting then dying shortly after.

The best way to prevent this from happening is to clean the fuel lines on a regular basis.

The ignition switch is also an important component of the mower, as it is responsible for supplying power to the engine.

If the switch is faulty, it can prevent the engine from receiving the power it needs to remain running.

This can result in the mower starting then dying after a few seconds.

Finally, the muffler is another important component of the mower, as it helps reduce noise levels and also helps keep the engine running smoothly.

If the muffler is damaged or clogged, it can cause the engine to not be able to produce enough power to keep the mower running, resulting in the mower starting then dying shortly after.

Best Practices for Troubleshooting

When your lawn mower starts and then dies shortly after, it can be frustrating to figure out the cause.

To ensure that you are accurately diagnosing the issue, it is important to follow a few best practices for troubleshooting.

First, make sure that you have the correct fuel mix.

Many modern lawn mowers require a fuel blend that includes both gasoline and oil.

If you are using the wrong fuel mix, this can cause your mower to start and then die shortly after.

Second, check the air filter.

A dirty air filter can restrict the air flow to the engine and cause your mower to start and then die immediately.

If the air filter is clogged, it should be replaced as soon as possible.

Third, inspect the spark plug.

A spark plug can become fouled or worn out over time, which can cause your mower to start and then die shortly after.

If the spark plug is not functioning properly, it should be replaced.

Finally, inspect the carburetor.

If the carburetor is not functioning properly, it can cause your mower to start and then die shortly after.

A damaged or malfunctioning carburetor should be inspected and repaired by a professional.

By following these best practices for troubleshooting, you can accurately diagnose the problem and determine if it is a simple fix or requires a more complex repair.

If your mower is still experiencing the issue after following these steps, it is best to take it to a professional who can diagnose and repair the problem.

Final Thoughts

Troubleshooting a lawn mower that starts then dies can be a tricky task.

By understanding the common causes of this issue, you can begin to diagnose the problem and take the necessary steps to get your lawn mower running again.

If you are unsure of what to do, it is always best to consult a professional for help.

With this knowledge, you can now take control of your lawn mower and get it back to its peak performance.

James Lopez

James Lopez is a lifestyle journalist. In addition to working as a journalist, he also takes courses in landscape design. He is pretty focused on the outdoor space, especially the backyard.

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