Lawn mower backfires then dies

Lawn mower backfires then dies. A backfire in a lawnmower is just like a small blast. Mostly it is not threatening, but the reasons behind this blast are dangerous for the engine.

Backfires occur surprisingly and mostly when you are switching on the lawnmower or switching off it after completing the work.

It is very important to know the basic information related to the backfire problem and how you can deal with it properly. It generally happens when the fuel approaches the spark from outside of the engine burning chamber.

If enough amount of unused fuel runs to enter the engine and approaches to spark, then it will catch fire, producing a small engine blast.

There are many reasons behind the lawn mower backfiring, mostly when it is overheated. So without any wait, let us discuss all possible problems and how we can fix them to save our mower from backfiring.

Lawn mower backfires then dies

lawn mower backfires then dies

Normally, a mower backfires means that there is additional air in the gas mix, which will lead to unfinished combustion. The gas that is sent to the exhaust will still hold gas.

When it approaches the exhaust, the gas will exnight impulsively and makes a big sound which is called backfire.

Here I explain the main issues of the lawnmower when it backfires.

Decreasing the speed of the engine fastly

It is a very important fact that you are if you are running a mower for one hour, then lowering the speed of the engine fastly can cause a backfire because the mower is already very hot.

So its only and simple solution is that slowly decrease the speed of sound.

Low-pressure fuel

Low-pressure fuel basically means that air is mixed in more amounts in the air-fuel mixture. If a mower is backfiring, then the reason behind it could be that the low-pressure fuel is pushed into the engine burning chamber.

Old fuel filters and faulty fuel pumps are the main causes of low-pressure fuel.

So you should change the old fuel filters and repair faulty fuel pumps. Your problem of backfiring the mower will be fixed if these are the causes behind this issue.

Backfire when switching on the engine

It is a very rare case to face a backfire when starting the engine. However, if it occurs, then possible it is an issue with the carburetor or with the Firewheel.

If the carburetor malfunction, then the engine will not start. The backfire will occur because of the flooding in the engine, and it is not hot to still catch fire in the exhaust.

If the engine of the mower still starts, then it influences the timing of the engine because the oil will start leaking because of the damage.

Clean the spark plug

clean the spark plug

If there is a clog in the spark plug, then clean its wires and chamber.

It will make sure that ignition will happen at the proper time and stops the backfires, which usually occur due to untimed ignitions.

Clean the fuel filter

It is also very necessary to clean the fuel filter of the lawnmower. If you have been using it for one year, then it is better to replace it.

Sticky valves

The basic purpose of the valves is to seal off the cylinder in the engine. Air and gas mixture is entered into the cylinder by opening one valve.

At the same time, the other valves are opened to exhaust gases to way out from the cylinder after the process of combustion.

Now, if these valves take some time to open, then these gases can backfire. These valves are an internal part of the engine, so it is not possible for you to repair or replace them.

So it is best for you to open and let this job be done by the professional who will open the engine and repair the valves.


The final thought on this topic is that the backfiring of a lawnmower is not a great thing to worry about because it is something like a small explosion.

If you want to prevent your mower from this troubleshoot,ing then take care of small things like slowing down the speed of the mower slowly.

There should be no fault or clog in the spark plug. If you can not be able to solve the problem, then hire a professional.

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