How to Fix Lawn Mower Sputtering? (Reasons And Solutions)

Does lawn mower sputtering make grass-cutting a challenging task for you? If yes, then this article got the solution.

Plenty of reasons can develop this issue, such as old fuel, bad spark plug, clogged carburetor, dirty fuel filter, etc.

But no need to take tension. You can easily solve these issues by cleaning or replacing the damaged parts or oil.

In this article, I will list the most common reasons for lawn mower sputtering. I’ll also provide easy solutions to get your mower running smoothly again.

So, let’s dive into the article.

Reasons For Lawn Mower Sputtering

When it comes to solving the issue, the first step is surely figuring out the actual problem.

So, here I’ve compiled the most common causes responsible for sputtering.

1. Moist Fuel Tank

A moist fuel line or fuel tank is one of the most common causes of lawn mower sputtering.

When there is moisture in the fuel tank, it can mix with the gasoline and prevent proper combustion.

This can cause the engine to sputter or even stop running altogether.

Moisture can get into the fuel tank if the gas canister is left outside and exposed to the elements.

What else? It can also cause if the gas cap is not tightened properly or through condensation.

Solution

To fix this issue, you need to drain the fuel tank completely.

Once you have done this, refill the tank with fresh fuel.

Also Read: Common Bad Boy Mower Belt Problems (Solutions And Tips)

2. Contaminated, Old Or Low-Quality Oil

Another cause of lawn mower sputtering is contaminated, old or low-quality oil. You should never use gasoline with more than 10% ethanol concentration.

This ethanol oil combusts quickly but can melt the mower’s plastic compartments. Resultantly it will cause the mower to sputter.

If the oil is old and has not been changed, it can become thick and sticky. So it will make it difficult for the engine to run smoothly.

Solution

You can utilize a fuel stabilizer to enhance the durability of your mower gas. However, it’s better to opt for high-quality pure gasoline.

In addition, you should consider going for the type of oil the manufacturer recommends.

3. Gas Cap Issue

A loose or damaged gas cap can also cause your lawn mower to sputter.

If the gas cap is not tight, it can let too much air enter the fuel tank. So, it will result in the formation of a vapor lock.

A damaged gas cap can also cause fuel to leak out of the tank, which can be a fire hazard.

Solution

To fix this issue, check your gas cap to ensure it is tight and undamaged.

If you find it loose or damaged, replace it with a new one.

4. Clogged Carburetor

If you use the lawn mower for a long time, the carburetor may get clogged or dirty. Mostly, the by-products of combustion cause it to get dirty.

If it happens, it may alleviate the efficacy of the engine and cause it to die or sputter.

Solution

To eliminate this issue, you need to clean the lawn mower carburetor. So, first, remove the carburetor and inspect for the clogged parts. 

Remove the debris with the help of a carburetor cleaner. It is easily available at most hardware stores. 

You can consider buying this carburetor cleaner spray.

5. Mower Deck Is Filthy

When the mower deck is clogged with grass clippings and other debris, it can prevent the blades from rotating properly.

Mostly, it occurs when the grass is either too tall or damp. So, this grass will be caked in the space inside the cutting deck.

This issue can block gas ventilation. And it will lead to sputtering.

Solution

To fix this issue, you need to clean the mower deck. This can be done with a scraper or a wire brush.

Additionally, it’s important to keep the blades sharp to prevent excessive strain on the engine.

6. Faulty Spark Plug Or Ignition System

The spark plug is a vital component in the ignition system of your lawn mower.

It ignites the air/fuel mixture in the engine cylinder, which is responsible for starting the engine.

If the spark plug is malfunctioning or damaged, it can cause your lawn mower to sputter.

Solution

The first step is to check the spark plug’s condition. If it is dirty, remove the filth with the assistance of a wire brush.

And if it is worn or damaged, you must replace it to resolve the problem. 

Before removing the spark plug, disconnect the spark plug wire and clean the area around the plug. It will avoid debris falling into the engine.

After that, remove the spark plug with a spark plug socket and inspect it for any signs of damage.

Changing the spark plug annually is also recommended to avoid such issues.

7. Dirty Fuel Filter

The fuel filter in your lawn mower keeps debris and impurities out of the fuel system.

After some time, the filter can become clogged with dirt and debris. It will prevent fuel from flowing smoothly to the engine.

This can cause your lawn mower to sputter, stall, or run roughly.

Solution

To fix a dirty fuel filter, find the filter in your lawn mower and remove it from the fuel line. 

Clean the filter thoroughly with a brush or replace it with a new one if it’s too dirty to clean.

8. Clogged Air Filter

The air filter is responsible for filtering the air that is pulled into the engine. Therefore just like fuel filters, they can get dirty after excessive usage.

If it becomes dirty or clogged, adequate air will not arrive in the engine chamber.

So, an imbalance of air and fuel may cause combustion issues and sputtering. 

Solution

To clean a clogged air filter, you can use a soap solution if it is made from foam.

And if it is manufactured from paper, you must replace it. Try to swap your lawn mower air filter once a year for optimal performance.

9. Dirty Fuel Lines

Fuel lines are responsible for providing the fuel to different parts.

If the fuel line gets blocked due to debris, they will not supply the fuel to the engine chamber.

Solution

Inspect the fuel lines of your lawn mower. Clean them if they have dirt or fuel gum.

And if they are not in a good position, you have to replace them with new ones.

Also Read: Bad Boy Mower Is Smoking (Possible Reasons And Fixes)

How To Avoid The Lawnmower Sputtering Issue? 

To avoid the lawn mower sputtering issue, regular maintenance is essential. It includes checking the air filter, fuel filter, spark plug, and oil level before every use.

It’s also important to change the oil and filter and fuel filters regularly, as the manufacturer recommends.

Moreover, keep the mower deck clean and free of debris and grass clippings to ensure proper airflow.

Additionally, always use fresh fuel with the correct octane rating and ethanol content recommended by the manufacturer.

Old fuel can cause issues with the engine, and incorrect fuel can lead to sputtering and other problems.

Frequently Asked Questions (FAQs)

Conclusion

Doubtlessly, lawn mower sputtering is a common but exasperating lawn mower problem. But if you follow the mentioned methods, you can easily eliminate this problem.

Finally, I must say that you should give proper time to regular maintenance. It will curb the chances of sputtering.