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Why Won’t My Lawn Mower Start? 6 Possible Reasons & Solutions

lawnmower in the middle of the garden

Maintaining a spotless garden is an everyday challenge for most—whether you are a gardener with a lot of experience behind you or a newbie with a new lawn mower ready for the first test run. Gardening requires hard work and devotion, and if you are passionate about everything that gardening represents, you must welcome all the problems that come with this hobby.

Lawn mowers are a gardener’s favorite tool, but even this unbeatable beast of a machine faces troubles from time to time. If your lawn mower is not starting—and you don’t know why—we’ve gathered some crucial information for you to learn, as these problems might have a simple solution.

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The 6 Possible Reasons Why Your Lawn Mower Won’t Start

1. Empty the Gas Tank

An empty gas tank is a very common problem of lawn mowers not starting. This problem may be one of the simplest and with it comes a very simple solution! Check the gas tank before you lose all your hope of starting the lawn mower back up. Even if you thought that it had enough fuel, it is possible that over a long period, the fuel evaporated.


Fill your lawn mower with fuel. Make sure you use new and fresh fuel because adding stale fuel can further damage your lawn mower.

broken lawnmower in the field
Image By: plew koonyosying, Shutterstock

2. Old or Stale Gas

Keeping the gas in your lawn mower constantly fresh is crucial for proper maintenance. Although it may not seem as important, having stale gas in your tank can cause many problems and even stop your mower from running correctly. Gas has a lifetime of about 30 days before losing its properties. Once the ethanol from the gas evaporates, the old gas can quickly cause corrosion or clog your carburetor.


Make sure your gas is up to date. Replace and maintain it frequently to ensure you are using the best fuel for your lawn mower and, that way, prolong its life. Try replacing the stale fuel right away with fresh gas.

3. Worn Out Battery

The battery on your lawn mower may have lost its power after a long winter. Batteries usually have a life span of 5 years, although you may experience problems sooner. If your lawn mower won’t start or the battery is not staying charged for long enough, you may need to replace the battery entirely.


If your battery is not staying charged for long enough or won’t charge at all, it may be time to buy a new battery. Replace the battery if you start noticing any of these signs of wear.

lawn mower on grass
Image Credit: Skitterphoto, Pexels

4. Clogged Carburetor

As mentioned above, stale fuel can significantly affect and hurt a lawn mower or any other machine. It can cause rust, leading to many problems and even permanent damage to your carburetor. Over a more extended period, stale and dirty fuel can lead to a clogged carburetor. After a long period without changing, gasoline can cause buildup in the carburetor, which may be why your lawn mower does not work correctly.


Drain the fuel entirely and give your carburetor a thorough clean before adding fresh fuel.

5. Faulty Spark Plug

The spark plug responsible for starting your lawn mower can have many possible issues that may cause your lawn mower to have starting issues. The spark plug may be loose, not making a connection, or even gunked up with dirt and debris.


Clean the spark plug and make sure to tighten it securely. You may need to change the old spark plug entirely, but first, make sure to clean the place where it will be installed.

Changing lawn mower spark plug
Image Credit: The Toidi, Shutterstock

6. Dirty Air Filter

If you want your carburetor to run properly and as long as possible without being replaced, you have to know how to maintain it correctly. Since a carburetor needs air for the engine to run, the carburetor won’t get enough air if the air filter is dirty. If your lawn mower stops working or cannot start, your air filter may be worn and debris could have found its way to the carburetor or engine.


Clean your air filter regularly, or replace it once you notice symptoms of wear and tear.

divider 7 Safety Measures to Take Before Troubleshooting

Before you start with any troubleshooting, make sure to take all precautions. Lawn mowers are big and possibly dangerous machines requiring an experienced person to handle them. If you are insecure and are trying to figure out a possible problem on your own, do that with caution and always follow basic safety measures.

Safety Measures

  • Use maximum caution when handling gasoline or petrol, as they are highly flammable gases.
  • Before removing grass from underneath the deck, disconnect the spark lead first.
  • Always check the manual before doing any work on your own
  • If the level of the fuel reaches the cap, drain the tank accordingly

Tips to Get Your Lawn Mower to Start

Before searching for possible reasons for your lawn mower to stop working, you can try a few quick tips that might do the trick. Sometimes a problem is just a simple fix that you can quickly resolve.


  • Replace the spark plug, or try tightening it more firmly
  • Change the air filter
  • Ensure no excess water is collecting on the tank’s bottom
  • Remove all clumps of grass from underneath the deck
  • Make sure your carburetor is screwed in firmly
  • Always use fresh gas

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Hopefully, after reading this article, you’ve gained some insight into all the possible reasons why your lawn mower may have stopped starting. There are many possible reasons for your land mower to stop working, although when troubleshooting, it may be best to start with a simpler solution first, as the simplest problems are the most common ones to occur.

All these possibilities may seem challenging and complicated at first, but they actually have logical and simple solutions.

Featured Image Credit: pikowal0, Pixabay


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