3 Reasons Your Lawn Mower Won’t Start After Winter (+Quick Fix)

The winter has subsided, and you need your lawn mower to be up and running, but it won’t start. There can be many reasons your lawn mower is not turning on, and if this is the first time you are facing this issue, don’t panic. 

One of the most common reasons for your lawn mower not starting can be that its battery has run out of charge. Another common reason can be the blockage in the carburetor. So, you can charge the battery before you start it and check if there is any blockage in the carburetor.

There can be many more reasons for your lawn mower not turning on after the winter break, and you have landed on the right article to get this issue fixed.

Lawn mower 1

Why is your lawn mower not turning on after winter?

The reasons for your lawn mower not starting after a long winter break can vary from the battery running out of charge to the carburetor blockage.

Let’s find out all the reasons in this article why your lawn mower is not turning on:

1. Carburetor issues

The carburetor is like the engine’s heart; if it is blocked, your engine dies.

It is here where the fuel and air are mixed before entering the engine.

And if this is getting blocked for some reason, your mower will not start any time soon.

Below are some reasons to help you understand why your mower’s carburetor is blocked.

A build-up in the carburetor

There can be a build-up in the carburetor if your mower is sitting idle for a long time with fuel inside it.

The fuel inside is stale and can seep into the float bowl, causing the blockage.

Dirt accumulation

Dirt can easily be accumulated in the carburetor if the engine is idle for a long time.

The carburetor is not supplied with enough fuel.

lawn mower fuel filter

The balance of the oil and air has to be spot on when it comes to properly running the engine.

If the ratio of oil and air is disturbed, which ideally should be 15:1 or 12:1, you might hear a popping sound, and vice versa can also cause problems for the engine to start.

Also read:16 Easy To Follow Steps To Clean Lawnmower Fuel Filter.

Overflow of fuel in the carburetor

If there is too much dirt in the fuel tank, it can obstruct the needle valve.

This can cause an overflow of fuel in the carburetor, and the needle valve is not closing on time.

For this reason, the spark plug will get wet, and the engine will not start.


Once you find out that the carburetor is blocked, you must clean it.

Clean the carburetor with a carburetor cleaner.

If it is too clogged and cleaning will not solve the problem, you will need to replace the carburetor.

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2. A dead spark plug

Lawn mower spark plug

The engine will not turn on if the mower’s spark plug is dead.

If you are wondering what a spark plug is, it is a device that ignites the fuel/air mixture, which is compressed in the combustion chamber by providing an electric spark. 

The spark plug is attached to the ignition coil, which provides the electricity(voltage) for the spark.

This is how the combustion process starts to kick-start the engine.

Let’s find out what to do if the spark plug is not working.

If your mower is sitting idle throughout the winter and you have not replaced your sparkplug for a long time, then chances are that your sparkplug has died.

It can happen because of several reasons, which we will discuss further:

Oil seeping into the combustion chamber

If your mower sits idle for too long and you have not removed the fuel before parking, the spark plug will get oily.

This happens when oil seeps into the combustion chamber, causing the spark plug’s tip to be soaked into the oil.

If your mower is already old, this is likely the problem.

Also read: 7 Ways To Drain Gas From Push Lawn Mower Without Siphon?

Overheating of the spark plug tip

The electrode of the spark plug can wear out due to overheating.

Overheating happens due to pre-ignition and when the cooling system is not working properly.

So the spark plug can stop working due to repeated overheating over some time.

Carbon build-up

Lawn mower spark plug fix

Carbon build-up can also be a reason for your spark plug not working properly.

There can be several reasons for the carbon build-up; for example, the air filter is dirty, you have driven your mower too much at low speeds, rich fuel/air mixture, or you have not started your mower for too long.

Inappropriate spark plug gap

If the gap is not calibrated properly in the spark plug, ignition can be a problem, and there will be extra stress on it which can wear it down quickly.


The only solution to this is to replace the spark plug. 

It can be done easily, and the spark plug is not that expensive too.

Always read the user manual for replacing the spark plug of the mower.

Below are some points which will help you replace the spark plug:

  • Make sure the engine is not hot before you touch it.
  • Try to start it through the spark plug after removing the wire.
  • You will need a wrench to take out the defective spark plug.
  • Now place the new one carefully. Ensure you don’t damage it by tightening it too much into the cylinder head.
  • Now start it after you attach the wire.

3. Your mower has a bad battery

Lawn mower power cord

The battery of a lawn mower helps start the internal combustion engines.

The battery is one of the most important components that enable your lawn mower to run its electrical parts.

If you are wondering why the battery of your lawn mower has gone flat, keep reading.

If your lawn mower is parked for a long time, especially in winter, the battery has likely gone flat.

If you see that the mower’s electrical system has gone down, there must be some problem with the battery.

Let us find out why the battery is not working.

The battery has run out of charge.

The lawn mower batteries are mostly lead-acid batteries and can not run without regular charge.

If the engine is not turning on, there is no way it can retain the charge because the current source is created by the engine only.

Since you had not turned the engine on throughout the winter, the battery has run out of charge.

The battery fuse is dead

Sometimes the fuse of the battery also wears out.

It can hinder its charging. So make sure to check that and replace it if it is damaged.

Corroded terminals

If your mower is sitting idle for too long, there can be corrosion on the battery. 

This is sometimes frustrating, but you will need to do some work to clean these because it will not allow take up the charge.

Loose terminal connection

Lawn mower bag

The wire connection must be strong and tight to work properly.

Corrosion or any residue will not help and hinder the charging.

The starter will not get sufficient current to function if the connection is not strong enough.


The first thing you need to do is get the mower’s battery charged.

You can also jump-start it if you don’t have a battery charger.

If the battery is corroded, you will need to clean it thoroughly. 

A baking soda solution or paste can help you clean the corrosion.

You can apply the solution with the help of a bush and then wipe it off with a rag once the residue is removed.

While cleaning, make sure nothing seeps into the cell.

Ensure all the wires are connected tightly, and everything is insulated properly.

You can check the output voltage of the battery by using the voltmeter.

If your batteries are completely dead, you must buy a new one.

Final thoughts

The carburetor, spark plug, and battery are the 3 primary things that need to be checked for your lawn mower not starting after a long winter.

The carburetor is supposed to be the engine’s heart; if it gets clogged, it must be cleaned.

Clogging can happen due to stale fuel and debris in the oil container.

So make sure you don’t leave your mower idle for a long time with fuel inside it.

Freezing of the fuel can also cause this problem, and this is another reason you should not leave your mower with fuel, especially in winter.

Carburetor blockage can lead to a spark plug malfunction due to several complications.

If the spark plug is faulty, it is wise to replace it as you will find it cheap and easy to replace.

It is very important to take care of the battery and ensure it has not run out of charge. 

The battery’s terminals need to be sealed to avoid corrosion if you are not using them.

The wire connection to the battery also needs to be strong to avoid any leakage of electric charge.

Why is my lawnmower turning over but not starting?

The reason for the lawnmower turning over but not starting can be the spark plug. 
It might be loose, disconnected, or dirty. 

Will low oil cause lawnmowers not to start?

You can start your lawn mower with low oil, but it can certainly cause some damage to the machine.

Reference: Lawn Mower Technology, Lawn Mower SafetyLawn MowingLawn CareMowing your lawn.


Hello everyone, My name is Richa and I am here to make you a better gardener by creating an in-depth and helpful resource for all the fellow gardeners out there. If I could help even a few people understand their plants better then I call it a success for my efforts.

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