Why is my lawn mower surging

Why is my lawn mower surging?

Are you frustrated with your lawnmower surging and cannot figure out why? Well, you are not alone. Surging is a common issue that every lawnmower owner experiences, including me.

Despite my best efforts to maintain and troubleshoot my mower, I still find myself hearing that annoying surging sound and a question came into my mind “Why is My Lawn mower Surging? If you are in the same boat, don’t worry.

In this blog, I will explore the various potential causes and solutions for your surging engine. Whether your lawnmower engine runs intermittently, revs up and down uncontrollably, or only surges under specific conditions, such as when it is hot or the fuel level is low, I will try to cover it all.

The most likely reason behind a surging lawn mower engine is a blockage in the fuel supply. So, let’s dive into the details and get your lawnmower running smoothly once again.

Why my lawnmower is surging? The Immediate Answer:

The lawnmowers start surging because the fuel-to-air mix ratio in the engine is unbalanced. The problem occurred when you are not doing the mandatory maintenance of your mower. Your carburetor starts malfunctioning due to dirt and other particles inside the carburetor.



The major reason for lawnmower surging is the blockage of fuel supply. The fuel-air mix ratio is unbalanced therefore lawnmower engine is surging. However, there are other possible reasons which are responsible for the engine surging. These reasons vary according to engine specs, to user handling, and also depend upon the last serving of the lawnmower. These possible reasons are:

  • Use of Bad fuel
  • Fault in the carburetor
  • Dirty Air Filter
  • Dirty fuel filter
  • Faulty Spark Plug
  • Water inside the Carburetor
  • Change Oil

To address the surging issue you might check all these possible reasons, for this purpose you need to check all these possible reasons step by step.


The first thing is always to use the correct and good quality fuel. If you use bad fuel whether it is gas or petrol it will reduce the performance of your engine and your engine life expires soon. So, always use the appropriate fuel which is mentioned in the instruction manual of your lawnmower or which is recommended by your lawnmower company.


Another major reason behind the surging of lawnmowers is the fault of the carburetor. The carburetor is the device that is used to mix the air and fuel in the combustion engine. The device is responsible to pass the fuel to the engine intake and if this part is defective your lawn mower is surging. You need to clean the carburetor.


If the air is dirty it does not provide the air to the carburetor, therefore the ratio of fuel and air mixture is unbalanced and your lawnmower starts surging. Therefore always check the air filter for any dirt and wear and tear and clean it or replace it.


Similarly, the dirt in the fuel filter hampers the supply of fuel in the carburetor therefore the engine of your lawnmower starts surging. You must replace or clean the fuel filter.


Another possible reason for surging is a fault in the spark plug. Sometimes your spark plug is malfunctioning and does not provide the continuous electric supply from the coil to the electrode therefore your lawnmower starts surging. In this case, you need to clean the spark plug or replace it with a new one. To learn about the cleaning of spark plug read the article about cleaning the spark plug on your own.


Sometimes when your clean your lawn mower and service your lawn mower by using pressured water. The water goes inside the carburetor and when you start the mower engine it starts surging. For this issue always cover the electric things and carburetor while cleaning and servicing your mower with water.


Another possible reason for the surging you do not change the oil on time which raises the temperature of the engine and it starts surging. If you do not change the oil on time it may cease your engine. Therefore always change the oil after completion of the mentioned working hours in the company instruction manual. You can also talk with the service guy at your mower company



The major reason behind the surging of your lawn mower is the malfunctioning of your lawnmower carburetor. The carburetor needs to be cleaned after an appropriate time because the low-quality fuel and dirt will disturb the air-fuel mixture ratio which is responsible for the surging. To clean the carburetor on your own follow these steps:

Step 1:

Remove the Air filter to access the carburetor

Step 2:

Close the fuel gauge and fuel supply line

Step 3:

Now remove the carburetor carefully

Step 4:

Dismantles the carburetor by using the screwdriver and spanner.

Step 5:

Clean the carburetor and its part from the inside with the WD-40 or another cleaning lubricant very carefully. In case no cleaning lubricant is available you also use petrol for cleaning your carburetor. Always be careful so that the pins in the carburetor do not get damaged or removed.

Step 6:

Inspect the carburetor carefully and if any part is damaged replace it with a new one.

Step 7:

Rinse all the parts of your carburetor and wait till all the parts of the carburetor are dry completely.

Step 8:

Assemble the carburetor and install it in the lawn mower.

Step 9:

Connect the fuel line and install the Air filter and now it is again ready to start the lawnmower to check if it is working properly or not.


Why is my lawn mower surging?

Your lawn mower may be surging due to a variety of issues such as a dirty carburetor, vacuum leak, clogged fuel system, or other engine performance issues.

How do I troubleshoot a surging lawn mower engine?

To troubleshoot a surging lawn mower engine, you may want to check for leaks, clean or replace the carburetor, inspect the fuel system, and check for any vacuum leaks.

What are the common causes of a surging lawn mower engine?

Common causes of a surging lawn mower engine include a dirty carburetor, fuel system issues, vacuum leaks, or problems with the engine’s air intake or breather.

How can I fix a surging engine on my lawn mower?

To fix a surging engine on your lawn mower, you may need to clean or replace the carburetor, inspect and clean the fuel system, and check for any leaks or clogs in the engine components.

What should I do if my lawn mower engine is still surging after troubleshooting?

If your lawn mower engine is still surging after troubleshooting, you may need to take it to a repair shop for further inspection and potential repairs, such as replacing the carburetor or addressing other engine issues.

Can a dirty carburetor cause a lawn mower engine to surge?

Yes, a dirty carburetor is a common cause of a surging lawn mower engine. Cleaning or replacing the carburetor may help resolve the surging issue.

How does a vacuum leak affect a lawn mower that is surging?

A vacuum leak can lead to a surging lawn mower engine by disrupting the air and fuel mixture, causing irregular engine performance and surging behavior.

What role does the fuel system play in a surging lawn mower engine?

The fuel system is crucial for the proper functioning of a lawn mower engine. Issues such as clogs, leaks, or fuel delivery problems can contribute to engine surging.

Should I inspect the intake manifold and breather for a surging lawn mower engine?

Yes, inspecting the intake manifold and breather is important when troubleshooting a surging lawn mower engine as these components can affect the engine’s air intake and performance.

When should I consider replacing the carburetor on my surging lawn mower?

If cleaning the carburetor does not resolve the surging issue on your lawn mower, or if the carburetor is heavily clogged or damaged, it may be necessary to replace it to restore proper engine performance.


It is very easy and convenient for you to do the basic maintenance of your lawn mower on your own at home. You will save money and time and additionally you do not need to transport the mower to the company service shop. To avoid any inconvenience, you need to do the maintenance of your lawnmower on time. Clean the spark plug, check the air and fuel filter, and clean the carburetor by doing these simple steps. Your lawn mower is working perfectly and you do not face any problems. The life and performance of your lawn mower also increased.

Naveed Aanjum author

About Naveed A Hashmi

In my childhood, I used to see my parents while working in the land, for these reasons today I have been serving the same as our own tradition and culture. I thus love to stay in it, because I want to learn something advanced and new so that I may improve my farm’s contour and help others with my experience.

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