Why Wont My Lawn Mower Start? Troubleshooting Tips You Need!

If your lawn mower won’t start, it is likely due to a clogged air filter or a bad spark plug. Lawn mowers require fuel, air, and spark to start and run.

A well-manicured lawn is an essential feature of any home. However, it’s frustrating when your lawn mower won’t start. A lawn mower that won’t start is a common problem, and it can be caused by different things. An air filter that is clogged with dirt, grass, or debris can prevent proper airflow and fuel combustion.

Similarly, a bad spark plug can prevent the engine from starting. Other possible reasons include stale fuel, a dirty carburetor, or an empty gas tank. This article will explore some of the common reasons why your lawn mower won’t start and what you can do to fix the problem.

Why Wont My Lawn Mower Start? Troubleshooting Tips You Need!

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Basic Troubleshooting

Is your lawn mower giving you a hard time starting? Fear not, as there are simple steps you can take to diagnose the problem. In this section, we will highlight the basic troubleshooting procedures to help you determine what is preventing your lawn mower from starting.

Checking For Fuel

  • Check if there is enough fuel in the tank.
  • If the fuel is over three months old, it may have gone stale and require replacement.
  • Make sure there are no clogs or blockages in the fuel line.
  • Ensure that the fuel shutoff valve is open.

Examination Of The Spark Plug

  • Locate the spark plug and remove it to inspect for signs of wear or damage.
  • A clean, dry spark plug is a good indication that it’s functioning correctly. If it’s dirty or wet, it may be failing and require cleaning or replacement.
  • Ensure that the spark plug gap is correct for optimal performance.

Assessment Of The Air Filter

  • Check if the air filter is dirty or clogged with debris.
  • A dirty air filter can cause engine misfires, reduced performance, and starting problems.
  • If the air filter appears clogged or dirty, replace it with a new one immediately.
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Inspection Of The Oil Level

  • Check the oil level to ensure that it’s not too low or too high.
  • Running the engine with low oil can cause severe damage to the motor, whereas having too much oil can cause leaking and starting issues.
  • Refer to the manufacturer’s instructions for the proper oil level and type for your lawn mower.

By following these basic troubleshooting procedures, you can quickly determine the cause of your lawn mower failing to start and take the appropriate action. Remember to be safe and disconnect the spark plug wire before undertaking any maintenance work on your lawn mower.

Significance Of Regular Maintenance

Maintaining your lawn mower regularly is essential to ensure it keeps running smoothly and efficiently. Regular maintenance not only helps to extend the life of your machine, but it also helps to prevent costly repairs down the road.

Importance Of Oil Changes

Just like any other piece of machinery, lawn mowers require regular oil changes too. Fresh oil helps to lubricate the engine, ensuring it runs smoothly. Your lawn mower’s manual will suggest how often it requires an oil change, but typically it would be recommended to change oil every 50 hours of operation or every season.

Tips to consider:

  • To ensure the oil drains quickly and completely, run the lawn mower for a few minutes before consumption.
  • Use the recommended type of oil for your lawn mower model as mentioned in the manual.
  • Always change the oil when the engine is cold.

Cleaning Of The Air Filter

Air filters play a vital role in preventing dust, dirt, and debris from entering the engine and causing damage. Dirt and debris can clog the air filter, restricting airflow to the engine. This lack of airflow causes the engine to work harder, putting a strain on the machine.

That’s why it is important to routinely clean or replace the air filter.

Tips to consider:

  • Follow your lawn mower’s manual instructions for cleaning and replacement of the air filter.
  • If you mow in a dusty environment, check and clean the air filter more frequently.
  • A clean air filter can improve fuel efficiency and extend the engine’s life.

Adjustment Of Belts And Spark Plug

Belts help drive the blades that cut the grass, while the spark plug ignites the fuel in the engine. Both these components need to be checked and maintained regularly to ensure your lawn mower continues to perform well.

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Tips to consider:

  • Check the belts for any signs of wear or damage, and replace if necessary.
  • If the spark plug is worn or dirty, it might not work correctly, so make sure to clean and replace it as per the manufacturer’s recommendations.
  • Always refer to the manual for instructions, and use proper tools to fix and replace the parts.

By following these regular maintenance steps, you can ensure your lawn mower is always in top shape and ready to tackle your lawn with ease. Neglecting these simple steps could lead to costly repairs or the complete breakdown of your machine.

Stay ahead of the curve and give your lawn mower the treatment it deserves.

Deeper Troubleshooting Methods

If your lawn mower refuses to start, you may need to perform a few deeper troubleshooting methods to isolate and address the issue.

Inspection Of The Carburetor:

  • The carburetor is responsible for mixing fuel and air for combustion in the engine. If it is clogged or dirty, the engine may not start.
  • Remove the air filter and inspect the carburetor. If it’s dirty, clean it with carburetor cleaner and a soft-bristled brush.
  • Check for clogs in the carburetor jets and fuel passages, and clear them if necessary.
  • Ensure that the float, needle, and seat are all functioning properly.

Analysis Of The Fuel Filter:

  • The fuel filter screens out dirt and debris from the fuel line. If it’s dirty or clogged, fuel may not reach the engine.
  • Locate the fuel filter and remove it from the fuel line. Inspect it for clogs or dirt, and replace it if necessary.
  • Check the fuel lines for any clogs or damage, and replace them if needed.
  • Clean the fuel tank to remove any debris or sediment that may have collected in it.

Examination Of The Ignition Switch:

  • The ignition switch is responsible for supplying power to the engine’s starter motor and spark plug. If it’s faulty, the engine may not start.
  • Test the ignition switch by turning the key to the “start” position while monitoring the battery voltage. If the voltage drops significantly, the switch may be faulty.
  • Check the wiring connections to the ignition switch, and repair or replace any damaged wires.
  • If the ignition switch is working properly, test the spark plug and starter motor to ensure they’re functioning correctly.

By performing these deeper troubleshooting methods, you can pinpoint the issue causing your lawn mower not to start and take the necessary steps to get it up and running again. Remember to always prioritize safety when conducting any repairs or maintenance on your lawn mower.

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When To Call A Professional

Reasons For Calling A Professional

Despite carrying out regular maintenance on your lawn mower, there are times when it simply won’t start. Frustration sets in, and diy repairs can sometimes make matters worse. In such cases, it’s essential to know when to call a professional.

  • Damaged or worn-out parts that require special tools to fix
  • Electrical or mechanical problems that require technical expertise
  • A problem that persists even after diy repair attempts
  • A need for professional diagnosis and advice

Choosing A Reliable Lawn Mower Technician

Hiring a reliable lawn mower technician is vital to ensure your machine lasts for years and offers its optimum performance.

  • Look for qualifications, certifications, and relevant experience.
  • Check for reviews and references from previous clients.
  • Ask for a written estimate of costs and services before hiring.
  • Confirm that the technician has the required tools and equipment to handle your specific lawn mower model.

Cost Of Professional Lawn Mower Maintenance

The cost of professional lawn mower maintenance relies on several factors, including the:

  • Size and complexity of the lawn mower
  • Number of hours spent on the repair or maintenance
  • Type and quality of spare parts required
  • Geographical location of the repair facility

It’s crucial to choose a professional that offers affordable rates without compromising on quality. To avoid hidden costs and unexpected billings, consider asking for a written estimate upfront. Also, ensure that the technician discusses the cost of potential spare parts that might need to be replaced.

Seeking professional help when your lawn mower malfunctions ensures that you have access to the right tools, expertise, and advice. Considering the tips above when hiring a lawn mower technician can save you time and money in the long run.


After reading this post, you now have a good understanding of why your lawn mower may not be starting. Remember to check the most common issues first like the fuel level, spark plug, air filter, and battery. It’s also important to keep up with routine maintenance tasks like sharpening the blades, changing the oil, and cleaning the deck.

By doing these simple steps, you can extend the life of your lawn mower and prevent frustrating start-up issues in the future. However, if you have tried all the mentioned steps and your lawn mower still refuses to start, it might be time to call a professional.

Don’t let a non-starting lawn mower ruin your day, take care of it and it will take care of your lawn. Happy mowing!