Lawnmower Starts Then Dies

Want To Know Why Your Lawnmower Starts, Then Dies Out Quickly? Take A Look

A lawnmower is a simple machine with high utility. This lawn care tool has very few components, which are quite sensitive and prone to defects. It is the reason why people who own lawnmowers, generally complain about frequent technical problems.

One of the recurring issues that you might face with your lawnmower is how it abruptly stops working, just after a short while of turning it on. So, let us analyze the most probable causes of this problem and what you need to do when your lawnmower starts, then dies.

Regularly mowing your lawn won’t just help make it look great, but will also keep your lawnmower healthy. Lawnmowers can accumulate a lot of dirt if they are not in daily use. While robotic lawnmowers are better in this regard, the old lawnmowers that operate on gasoline can cause a lot of trouble. Let’s discuss how to solve the issues of starting an old-style lawnmower, which has been in a dormant state for long.

Possible Causes And Solutions

1. Problems With Carburetor

a. Dirt Accumulation
In most cases where the lawnmower starts and then dies out, the problem lies with the carburetor, which is why you should first check whether it is fixed properly in the machine or not. Later, you should clean the carburetor with a carburetor cleaner, so that all the dirt is removed. Excess dirt does not allow the atomization of the gas inside the carburetor. This prevents the gas from reaching the engine, which means you cannot rev it, and thus, it does not work.

b. Fuel Not Replaced
Ideally, one should frequently replace the fuel inside the lawnmower’s tank. This is done because when gasoline is present inside the lawnmower’s tank for a long time, it loses its volatile component due to evaporation. Later, only sediments of other components are left, which clog the carburetor and do not allow it to work.

To replace the fuel, you need to empty the lawnmower’s tank, and then put fresh fuel inside it with a fuel stabilizer. The fuel stabilizer protects the volatile components by preventing evaporation. Thus, the gasoline can last longer without needing replacement. Using a fuel stabilizer can help in keeping the fuel efficient for up to two years.

c. Problems With The Bowl
The lower part of the lawnmower carburetor has a bowl, supported by a screw and a hole. It is through this hole that the fuel gas passes from the carburetor to the engine. If the hole gets clogged, the gas will not move downwards, or underneath the carburetor.

To solve this problem, remove the carburetor bowl screw with a wrench. Then, spray some carburetor cleaner to scrape off the dirt from the hole. You might require a thin wire to do the scraping. Once you are through, recap the bowl on the carburetor, but do not tighten the screw excessively because it will not allow the gas to pass through.

d. Carburetor Needs Replacement
If you have not used your lawnmower for years, there are high chances that the carburetor has worn-out, and it is unable to properly mix the gasoline with the air for revving the engine. In this case, do not start repairing the carburetor forcefully, at least if you do not know how to detach the carburetor. It can damage other working parts of the lawnmower.

To detach the old carburetor, you should first pinch the gas hose. This will prevent gasoline from falling into the carburetor. Next, firmly fix the new carburetor to the machine. We recommend that you remove the cap of the spark plug before you start adjusting the carburetor, for safety purposes.

2. Issues With The Spark Plug

Check the spark plug of the lawnmower and use a new plug if you see that the old one is burnt out or degraded. The degradation of the lawnmower’s spark plug is usually because of carbon buildup inside the socket.

Carbon does not allow the spark to ignite inside the spark plug, and therefore, the plug is unable to supply enough power to the engine. Consequently, the lawnmower starts, but turns off shortly afterwards because of insufficient torque generation in the engine.

Cleaning the spark plug is essential so that you do not allow carbon to build up inside the sockets. If the carbon depositions become exceedingly large, the spark plug will not work, and you will have to replace it.

3. Problems With The Gasoline Cap

Lawnmowers have a gasoline cap that separates the fuel tank from the carburetor. Generally, every gasoline cap has a hole to maintain pressure in the carburetor. However, with time, the hole can get clogged. It won’t let the gas enter the carburetor, and thus, the lawnmower won’t work. Therefore, you should check the condition of the gasoline cap regularly, and clean it occasionally, with a thin wire. . Also, if the gasoline cap is damaged, replace it immediately.

4. Excess Oil

If the lawnmower starts and then dies out, it could be because you’ve added too much oil in the lawnmower tank, causing it to not circulate evenly. Even after cleaning the carburetor thoroughly, if the problem persists, there are high chances that you have put too much oil in the oil reservoir.

To check whether your lawnmower’s tank has excess oil, tilt the lawnmower and keep a heavy object against its handle to hold it up. After a few hours, start the lawnmower and check if it dies out quickly again or not. If the lawnmower starts working fine, you had put excess oil in the reservoir that could not circulate to all parts of the machine until you tilted the lawnmower.

You can also use a dipstick to check the oil levels in the reservoir. If you feel that the oil inside the tank is in excess, you can tilt the lawnmower, and remove the excess oil into a container to use it next time.


If your lawnmower starts then dies and is not running properly, you should follow our guide and look for the possible causes of this problem. While riding lawn mowers have an electric ignition system, for the traditional lawnmowers, the carburetor alone is the most pivotal part. So, its malfunctioning prevents the lawnmower from operating normally. Therefore, keep it clean, prevent it from clogging, and half your problems are solved right there.