6 Reasons Why Lawn Mower Starts Then Stops

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Your lawn mower starts then stops?

Everyone would love that fresh-cut grass smell as they cut trim their lawn grass.

However, not everyone experiences this when their lawn mower turns out faulty.

As much as mowing is a fun and simple activity, it can turn to frustration when the lawnmower does not function as expected

This happens to many people, so don’t feel like you are the only one going through this.

When the mower starts then stops, there could be many reasons why this is happening.

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In this article, I’ll discuss some of the causes that may lead to lawn mower stopping.

Let’s get started;

Reasons Why Lawn Mower Starts Then Stops

Below are some of the most common reasons why your lawn mower stops just some minutes after starting.

1. Check the Carburetor

If your lawn mower starts then stops, the problem might be the carburetor.

The work of the carburetor is mixing gas with the correct amount of oxygen, leading to combustion.

The combustion enables continuous rotation of the crankshaft that is responsible for running the engine.

If the lawn mower starts then stops, the problem might be in the carburetor or the parts attached.

Note that when the carburetor is loose, the engine does not function accordingly due to insufficient gas flow.

Ensure your carburetor is firmly fixed before going any further.

The other issue that may be in the carburetor is accumulated dirt.

Often, dirt and grime tend to build up in the carburetor that causes the mower to stop immediately after starting.

To deal with this issue, use carburetor cleaner to clean all the dirt.

2. Clogged Carburetor Bowl

Nowadays, most carburettors have their bowl underneath with a screw at the bottom with a hole that gives the bowl support.

Once the hole in the screw becomes clogged, air does not pass from under the carburetor, thus poor regulation of downward gas movement.

To clean the bowl, remove it using a ½ inch plug wrench and use a thin wire to remove the dirt on the hole.

Later spray the hole using a carburetor cleaner.

Avoid over-tightening the screw to avoid seal distortion.

3. Old Gas with Residues

When gas is left for a long time in the lawn mower’s tank, it forms residue after evaporation of the volatile component.

The residues left to clog the internal parts of the carburetor blocking the flow of gas.

To fix this drain all the old gas then put fresh one and a fuel stabilizer. A fuel stabilizer prevents residues by enhancing the fuel quality for a period of two years.

4. Dirty Of Defective Spark Plug

Lawn Mower Starts Then Stops

This is mainly due to carbon build-up in the socket of the spark plug that weakens the spark plug.

Check whether the spark plug is degraded or has burnt out.

In case you find that the spark plug is degraded, then it is time to replace it.

If it is okay, clean it by wiping the carbon deposits and the oil accumulated on the plug.

You can replace the spark plug as you replace the engine oil, let’s say every year.

Replacement is an easy task; you need to unhook the spark plug wire and remove the old plug using a spark plug socket.

With the use of a spark plug gauge, measure the gap between the 2 electrodes at the tip of the spark plug.

Check out manufacturer specification for your model to determine the recommended gap size.

If need be, use a plug gauge when adjusting the gap by bending the curved electrode slowly.

You are now ready to install the new spark by attaching it to the plug lead.

Always ensure you don’t over-tighten it for effectiveness.

5.  Blocked Gasoline Cap

As the engine consumes fuel, the level in the tanker lowers,

The gasoline cap through a small vent allows air into the tank.

When the cap vent becomes clogged, the air cannot enter the tank creating a vacuum.

This leads to an unsteady flow of fuel to the carburetor leading the engine to stall.

To find out whether the cap vent has clogged, loosen it slightly, then start the engine.

If the engine starts and keeps running after loosening the cap, the cap is clogged.

6. Excess Oil In The Reservoir

Sometimes the cause of your lawn mower starting then stopping after a few seconds is too much oil in its reservoir.

If you there is a white smoke coming from the engine, that is a sign of excess oil.

Your mower might run for the first few minutes, then stop as the extra oil drowns out the engine making it to die.

To fix this, you only need to drain some of the oil using a siphon.

For a walk-behind mower, the oil can be drained through the hole you use when adding the oil.

Ensure you don’t remove all the oil in the reservoir as it can bring another problem.

Always use a dipstick to measure the oil level and ensure that it in the right level.

If, after draining some of the oil, the mower keeps running without stopping, you will fix the problem.

Final Thought On Lawn Mower Starts Then Stops

I hope you have some ideas on why your lawn mower starts then stops.

Always start by checking some of the most obvious reasons once your mower stops running.

Ensure your lawn mower is well maintained by cleaning the necessary parts regularly, replacing any worn out part, among others.

Do not overfill the engine oil, and keep the gasoline and oil clean for good functioning of your mower.

If you’ve tried all the above and the mower still stops after starting, then it’s now time to call an expert.

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