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The Reason Why Lawn Mower Starts Then Dies

by Richard

Recently, gardening has become much easier thanks to the lawn mower. That’s why many people have chosen this solution to support a better job. However, the fact that sometimes your lawn mower starts then dies is inevitable, no matter how properly you start the machine. So, what are the causes of this problem? And how to solve it simply and effectively? Let’s scroll down to find more.

The Reasons Why Lawn Mower Starts Then Dies

After a period of use, your lawn mower might not be as good as it used to be. One of the most common problems you may face is the machine starts then dies right away.

This problem can stem from many different causes. Details as below:

Have Problems With Spark Plug

This should be the first reason why your lawn mower doesn’t function. In this case, it may be lost fire, damaged BXC (Carburetor), or lost steam replacing the spark plug.

To accurately check whether spark plugs have sparks or not, professional mechaníc may need to use a specialized tool. However, based on the color of the spark, it is also possible to determine the condition of the spark plug.

The standard spark for all types of engines must be blue and not light red. It does not last long but must be strong and decisive.

If there is a loss of fire, check if the spark plug you are using is dead or not, replace it with a new one, and conduct the fire test as above.

Should there be still no fire or weak fire, then look over the spark plug cable to see if it is in good contact or not.

If the cable is good, you can continue to check the coil by using some specialized tools, such as a 2-head screw (screwdriver), 10-12 buckle (wrench),  pliers, and handle.

Spark plugs need to be audited and cleaned periodically. This helps you recognize the engine’s condition and make timely adjustments to always achieve the highest working efficiency.

When cleaning, it is necessary to clean the carbon layer clinging to the electrodes and adjust the ignition gap between the two electrodes.

Audit Steam Unit, Cylinder

This could be one of the causes why your lawn mower starts then dies.

In this case, people usually use specialized tools to test the cylinder pressure. Experienced mechanics can even use their hands to check. In short, this is a sign that you should take note.

Adjust Carburetor Gasoline Wind Improperly

Improper fuel adjustment on the carburetor might be a possible reason why your lawn mower starts then dies. So, what should we do here?

– Gently turn screw H (special screw to adjust the maximum speed of the mower engine) clockwise. Remember to rotate gently until the screw closes completely. After closing, continue to swivel gently counter clockwise for one or half turn.

–  Slew the L screw gently  (specialized screw to adjust the speed of the car) clockwise until it closes completely. Note, you must not use too much torque; or else, it will damage the adjusting screw. Once closed, continue to swivel counterclockwise one turn or quarter turn.


– From the default H, L positions, only clockwise adjustments can be made to a maximum of ¼ turn; otherwise, the motor will be severely damaged.

– When adjusting the L screw, the Garanti screw must be adjusted accordingly because these two screws are related to each other.

– For each adjustment, just turn 1/16 turn, then check whether the change is appropriate. If not, continue with 1/16. Do not twist at a time too fast or too strong, it will damage these screws.

Use Of Improper Gasoline And Oil

Besides, the use of inappropriate fuel will cause the engine to stall, which is also a factor affecting the problem mower would not start.      

For lawnmowers with 2-stroke engines, the fuel needed is gasoline mixed with viscous oil. As for the 4-stroke engine, it is completely gasoline. So be careful when using it. When your lawn mower starts then dies, you must check whether the fuel has met the requirements and reached the ratio or not.

The most suitable and recommended gasoline is A92 or A95. In addition, the best lawn mower oil should use the supplier’s oil to be more secure.

In some cases, the lawnmower can not start because of excess oil, so we must adjust the amount of oil in the fuel accordingly.

Not Clean Machine

Periodic maintenance is an important factor in maintaining the life of your lawnmower. By servicing your lawn mower regularly, you will improve its performance and prolong its life

Before you begin, you’d better check a close visual inspection, clean any debris, then:

– Tighten or replace another new one in case of any loose bolts or nuts.

– Paint rusty textured parts.

– Replace or cover any frayed or bare wiring connections.

– Remove the spark plug lead from the lawn mower spark plug and move it away from the cylinder head.

– Change or sharpen the blade as needed.

– Check the engine “air filter” during maintenance.

– Renovate the oil if necessary. If your mower is a “four-stroke” model, alter the oil at least once a year.


Through this article, we have listed the most common reasons why your lawn mower starts then dies. Basically, you can base on our above advice to fix this problem. However, if you have tried all of them but it still doesn’t function smoothly, we suggest taking them to a mechanic for repair.

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