Why my lawn mower won’t start? 7 Common reasons & DIY remedies for you

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The lawnmower won’t start is a common problem. There are some reasons for the lack of performance. Most of them come from a humid working environment. Besides, bad maintenance can reduce the lifespan of a lawnmower. You needn’t take it to the repair service. This article will tell you what to do in this case. 

Your lawn mower won’t start after the winter?


After the winter, you will have some difficulties starting the engine. There are some common reasons for the problem:

1. You don’t drain the gas out 

If the gasoline sits in the fuel tank for a long time, it will produce debris. That will help build up a clog in the carburetor. 

Moreover, the stale oil can go through all the parts of the carburetor. The debris and dirt can damage the parts. 

The manufacturer recommended that you should drain all the gasoline out. Removing the gasoline after it is stale may be difficult. In addition, you can add some stabilizers to the fuel tank to prevent the clog.

To drain the gas out, you should follow this guide.

2. The spark plug is broken

The remaining fuel can exhaust the gas that is harmful to the spark plug. On the other hand, the electrode of the spark plug is melted. In this case, you should change a new spark plug for your mower.

3. The battery is out of order

The average lifespan of the battery is about five years. For a good ignition, you should charge the battery regularly. If the battery isn’t corresponding to the charger, you should replace it with a new one. 

In the winter, although you do start the engine or don’t, the power of the battery will gradually lose. In fact, in the spring, when you try to start the engine, the battery dies.

Lawnmower won’t start after running?

This would be a shock to you if your lawn mower won’t start after running. The problem is coincidental. It may be not related to the previous failure. The problem can come from every part. 

Here are some possible reasons why your lawn mower won’t start:

  • The fuel is under the proper level: Look at the fuel tank and check it.
  • The carburetor is clogged: There is some debris in the fuel. They can damage the piston and the related parts. To avoid this situation, you should clean the carburetor regularly.
  • The grass is so tall that the blades can’t work: The grass clogs up the mower, so the engine stops. You should adjust the blades to a higher position to fix the problem.
  • The spark plug may be in bad condition. Cleaning the spark plug helps enhance the performance instantly.
  • The filter is clogged. The airflow is restricted. The fuel can’t burn because of a lack of oxygen. 

7 Common reasons for a lawn mower that won’t start 


Sometimes you will have trouble starting the lawnmower. However, you needn’t take it to a costly repair shop. First, go through the seven common reasons. Then we will tell you how to deal with the problem.

#1: There is no fuel

It may be a crazy thing, but somebody has caught the case. Open the fuel tank and check the fuel level. Add some more if needed.

#2: You have a bad carburetor

If you haven’t changed the fuel for 30 days, you may have some problem with the fuel’s quality. At that time, the gasoline can cause corrosion that damages the carburetor. Moreover, the debris can lead to a stuck in the piston.

#3: The fuel filter is in poor condition

The filter helps filter out the sediment. However, if you don’t clean the filter for a long time, it can be clogged. In this case, the fuel flow won’t be steady. You don’t have enough power to start the engine.

#4: The battery is out of power

Let’s use a voltage to check the condition. If you have a 12V battery, the number on the voltage should be close to 12V. If you have a smaller number, it’s time to have a charge.

#5: The solenoid dies

A bad solenoid gives you some difficulties starting the engine. In this case, you will hear the clicking sounds when you rotate the ignition key. 

#6: There is something wrong with the spark plug

On one hand, the problem may come from a lack of connection between the spark plug and the ignition wire. On the other hand, it can come from the dirty spark plug. Let’s have one minute to check the spark plug. Clean it if it is dirty. Replace it if it is worn.

#7: You don’t clean the air filter for a long time

A dirty air filter will restrict the airflow. Moreover, the debris can go through the air filter and come to the carburetor. Therefore, the engine will be stuck. Recommendation: 2 Effective methods to clean mower paper air filter quickly.

What to do when a lawn mower won’t start?

If you do not know What to do when your lawn mower won’t start, you should follow the steps below:

Before troubleshooting your lawnmower

Before starting the repairs, you should have some preparation to protect yourself. You should notice that:

  • The gasoline is flammable. If it meets a hot object such as stoves, sparks, cigarettes, it will burn immediately. You should drain the gas out.
  • Cut the connection between the spark plug and the ignition wire. This helps prevent the engine from starting suddenly.
  • Clean the deck and the blade and change the oil. This enhances the performance of the lawnmower. 

Check the plug

To check the plug, you should have a plug tester. This is the most convenient and effective tool for you. To do this, you can follow the below steps:

  • Disengage the lawnmower.
  • Extract the casing.
  • Locate the spark plug.
  • Pull the ignition wire to disconnect it from the spark plug. The ignition wire shouldn’t meet any metal surface.
  • Place the tester between the spark plug and the ignition wire. The tester should connect to the metal surface.
  • Turn on the engine.
  • If you can see the fire while you start the engine, it proves that the spark plug is in good condition.
  • If there is no fire, you should replace it with a new one.

Clean or replace the filter when

The filter is between the engine and the carburetor. Therefore, if it is dirty and clogged, the airflow will be restricted. Let’s have a check on the filter. If it’s still in use, you can’t clean it. If it is worn, you should replace it.

The below process can help you:

  • Remove the top casing.
  • Extract the filter.
  • Look at the filter to check it.
  • If the paper filter is clogged or full of holes, you should replace it.
  • If it is a foam filter, you can clean it with dishwasher liquid.
  • Install a new filter if it is necessary.

Refill the gas tank

In the case that the lawn mower won’t start, you can try fixing it by refilling the gas tank. 

  • First, you find the fuel tank under the seat. Some tank is at the front or side of the engine. 
  • You can see a symbol of gasoline on the cap of the tank.
  • Open the fuel tank.
  • Use a funnel to add the fuel into the tank. The fuel helps you do the work without spilling.
  • Install the cap. Then use a screw to tighten the connection.

Tips to make your lawnmower start


The right process helps you start the engine fastest. You don’t have to force. The following guide is a useful one.

Case 1: You fail to start the lawnmower at all

The causes:

  • The bales are disengaged.
  • The spark plug’s connection isn’t good.
  • The lawnmower ran out of fuel.
  • The primer is broken. (Related post: How to prime a lawn mower without a primer bulb?)

The effective remedy:

  • Engage the blade.
  • Make sure that the spark plug’s connection is good.
  • Add the high-quality gasoline into the tank.
  • Enhance the primer operation.
  • Adjust or replace the failure parts.
  • Leave the lawnmower to rest for a few minutes, then start it.

Case 2: The lawn mower runs erratically

The cause:

  • The spark plug is in poor condition.
  • The fuel flow is clogged.
  • The engine is stale because of the water or the debris.
  • The air filter is dirty.

The effective remedy:

  • Tighten the spark plug’s connection.
  • Drain out the oil and gasoline. Then add in the tank some fresh gasoline.
  • Clean the vent and the air filter.

Case 3: The lawn mower is overheat

The cause:

  • The oil level is lower than the necessary level.
  • The filter is clogged.

The effective remedy:

  • Pour fresh oil into the fuel tank. Make sure that it is at the proper level.
  • Clean the air filter if it is dirty. Replace a new one if it has some holes.

Case 4: The lawnmower cut unevenly

The cause:

  • There are some problems with the wheels.
  • The blade is dull.

The effective remedy:

  • Confirm that the four wheels are in the right position.
  • Sharpen the dull blade. Replace it if it is necessary.

Final thoughts

Now you have effective ways to deal with a lawn mower that won’t start. The guides come from a mechanism that has various knowledge about lawnmowers. Let’s do everything step-by-step. Keep calm and keep up with the steps!

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