Why my lawnmower is revving high

Maintaining a beautiful and lush green lawn in your home or for commercial use, it is obvious that a lawnmower is mandatory equipment to mow the grass. Lawnmower is a complex machine and sometimes it develops faults. One of the most common problems is the REVVING HIGH while mowing and your mower acts like a car while you start mowing.

In this blog post, I will discuss the “FIVE MAIN REASONS BEHIND HIGH REVVING IN LAWNMOWER” and also provide a practical solution that you can perform easily at home and solve this problem. After reading this and following the steps I will briefly, you will be able to control the lawnmower’s throttle again at your ease.


In lawnmowers, revving refers to the engine running at a higher revolution per minute (RPM) as compared to normal. RPM is related to the speed of engine crankshaft rotation, which rotates too high in a minute. Revving is very annoying and due to this, you are unable to shape your lawn correctly. Revving is alarming sometimes and you need to fix it as early as possible to avoid any bigger problems in the engine.


There are precarious reasons behind lawn mower revving, however, I will discuss the main five reasons behind this problem. Generally, after resolving and checking these reasons you are able to get rid of this annoying revving in your mowers. The Five main reasons are:


The most important reason behind the lawnmower revving is the issue with the airflow system. The airflow system provides air to the combustion system. If this system is blocked or clogged your lawnmower starts surging.

Generally, people are using mowers for a long time without maintenance and Air Filter is completely clogged and deteriorated and blocking the air to flow inside, due to which the engine starts revving and another associated problem encountered in the lawnmower.


Step 1: Locate the Air Filter and dismantle the casing and remove the air filter.

Step 2: Inspect the Filter condition and clean it properly if not deteriorated.

Step 3: if your filter is completely deteriorated and damaged you need to replace it. Filter is a commonly available item so you can order online or just go to the market and buy two or three for a backup to use in an emergency.

Step 4: Reinstall and fit the air filter casing and start the mower and start working.


In a combustion engine, the carburetor is the main part that mixes the air and fuel to a ratio for combustion. For an accurate combustion, it is very important the carburetor is working perfectly.
The second main reason behind revving is the wrong adjustment or clogging of jets in carburetors due to which the RPM of the engine increases and combustion is disturbed. These air jets are small holes that provide fuel route and also measure and provide the exact fuel for combustion. Surging and stalling are also started in the mower if the carburetor is malfunctioning.


Step 1: Locate the carburetor, if you are new you may read the service manual of your lawnmower to locate the carburetor.

Step 2: After inspecting the carburetor, you noticed that there are two screws, these two screws are the main part to adjust the setting.

Step 3: One screw can control the speed, while the second screw modifies the idle mixture.

Step 4 : Start the lawnmower, and start adjusting by regulating the screws tighter and looser, move the screws slowly and carefully listen to the sound of your mower. Adjust both screws and when your mower is revving normally stop adjusting.


Another main reason behind lawn mowers’ high revving, is the bad or old fuel. Some people are using their mower after long breaks and do not change the oil. This will affect the engine’s health and due to the combustion phenomenon the engine starts revving high.


Step 1: Drain all the oil from the fuel tank. (Do not drain on the floor, always use a fuel container).

Step 2: Clean the fuel tank, it is very important to inspect the tank. If your fuel tank is rusted it means you need to replace the tank because a rust particle goes inside the engine with the fuel and damages it.

Step 3: Use the new recommended oil and start mowing your lawn.


The fourth main reason behind high lawnmower revving is the malfunctioning of the Governor. The governor is used to regulate the speed of the engine in lawn mowers. If adjustment is out, your lawnmower is revving high.


Step 1: Switch off the lawnmower, and remove the spark plug to avoid any accident.

Step 2: Locate the governor, and take help from the service manual if you are new.

Step 3: Inspect the governor for any leakage, damage, and visually deteriorated.

Step 4: Replace the governor if you find it damaged, sometimes the governor spring is broken, replace it with a new one.

Step 5: Adjust the tension of the governor by using the screw which is responsible to hold the arm.

Step 6: Close the work and clean the working area. Install the spark plug and start the lawnmower and hear the revving sound if it is still revving adjust the tension again.

Damaged Throttle (Race) Cable

The fifth main reason is the throttle cable issue, when you are using a mower for a long time without necessary maintenance it is going to start malfunctioning. The throttle cable is connected with the throttle on one side and the other side is connected to the engine. Sometimes the cable is broken or loosened from the engine side and is responsible for revving high issues of lawnmower.


Step 1: In the first step, visually inspect the cable. Sometimes tightening the nut connected to the engine can resolve the problem. After inspecting check if is fitted inside then you need to remove the primary parts like filters and then remove the cable.

Step 2: Replace the cable, the throttle cable is not much expensive and easily available locally so you have a better option to replace it instead of lubricating.

Step 3: Reinstall and start the lawnmower, start giving throttle slowly, and hear the revving sound. If it is working smoothly it means the revving sound is due to high race and throttle cable issues.


In a nutshell, understanding why your lawnmower is revving high is crucial in order to resolve the problem and ensure the smooth operation of your mower. I discussed the five main reasons for a high-revving lawnmower, including issues with the airflow, the carburetor, fuel, the governor malfunction, and in the last throttle cable damage. These are the basic and main reasons and I also provide you with the best possible solution you can do at your home.

By considering these main reasons and conducting thorough inspections, you can effectively troubleshoot and resolve the high revving problem with your lawnmower hassle free on your own.

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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