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5 Common Lawn Mower Repair Issues and How to Fix Them

5 Common Lawn Mower Repair Issues and How to Fix Them

Here’s an overview:

Introduction to Common Lawn Mower Repair Issues

When it comes to maintaining a beautiful and healthy lawn, a properly functioning lawn mower is essential. However, like any other piece of machinery, lawn mowers can experience issues that may require repair. Understanding common lawn mower problems can help you identify and fix them efficiently, ensuring your lawn mower stays in top condition. Here are some of the most prevalent lawn mower repair issues to be aware of:

  • Clogged Air Filter: A clogged air filter can restrict airflow to the engine, leading to poor performance or failure to start. Regularly cleaning or replacing the air filter can prevent this issue.
  • Dirty Spark Plug: A dirty or faulty spark plug can cause problems with starting and running the lawn mower smoothly. Cleaning or replacing the spark plug can often resolve this issue.
  • Old or Contaminated Fuel: Using old or contaminated fuel can lead to fuel system clogs, which in turn can prevent the engine from starting. Draining old fuel and replacing it with fresh, clean fuel can help resolve this issue.
  • Dull Blades: Dull mower blades can tear rather than cut the grass, resulting in an uneven or ragged lawn appearance. Sharpening or replacing the blades regularly can ensure a clean and healthy cut.
  • Faulty Ignition System: Issues with the ignition system, such as a malfunctioning ignition coil or starter solenoid, can prevent the lawn mower from starting. Checking and replacing faulty ignition components can help restore proper function.

By familiarizing yourself with these common lawn mower repair issues, you can be better prepared to troubleshoot and address any problems that may arise, keeping your lawn mower running smoothly for years to come.

1. Engine Won’t Start

If your lawn mower’s engine won’t start, here are a few common issues to troubleshoot:

  • Check the Spark Plug: A faulty spark plug is a frequent culprit for a lawnmower that won’t start. Remove the spark plug and inspect it for signs of damage or wear. Consider replacing it with a new one to see if that solves the issue.
  • Inspect the Fuel System: Check if there’s fuel in the tank. If the mower has been sitting idle for a while, the fuel may have gone bad. Consider draining the old fuel and replacing it with fresh gasoline. Also, check the fuel filter and ensure it’s clean and unclogged.
  • Clean or Replace Air Filter: A clogged air filter can prevent the engine from starting. Remove the air filter and clean it. If it’s too dirty or damaged, replace it with a new one.
  • Examine the Carburetor: The carburetor may be clogged with dirt or debris, preventing the engine from starting. Clean the carburetor thoroughly to ensure proper fuel and air mixture for combustion.
  • Check the Safety Features: Some mowers have safety features like a dead-man switch or blade engagement system. Ensure these features are properly engaged or disengaged for the mower to start.

By troubleshooting these common issues, you can likely identify and rectify the reason why your lawn mower’s engine won’t start.

2. Poor Cutting Performance

When a lawn mower starts to display poor cutting performance, it can make your yard look untidy and unkempt. Below are common reasons for this issue and how to address them:

  • Dull Blades:
    • Over time, mower blades can become dull, resulting in ragged cuts on grass blades. Sharpening or replacing the blades can significantly improve cutting performance.
  • Uneven Deck:
    • An uneven deck can cause the mower to cut grass at varying heights. Ensure the deck is level by adjusting the deck height or checking for any debris obstructing the deck’s movement.
  • Clogged Deck:
    • Grass clippings and debris can accumulate under the mower deck, reducing cutting efficiency. Regularly clean the deck to prevent clogs and maintain optimal cutting performance.
  • Worn Belts:
    • If the drive belt or blade belt is worn or damaged, it can affect the mower’s cutting ability. Inspect the belts for signs of wear and replace them if necessary to restore cutting performance.
  • Engine Speed:
    • Running the mower at too low an engine speed can result in poor cutting performance. Increase the engine speed according to the manufacturer’s recommended settings for efficient cutting.

Addressing these common issues promptly can help restore your lawn mower’s cutting performance and ensure a well-maintained yard.

3. Excessive Vibration

Excessive vibration in a lawn mower can lead to discomfort during operation and may indicate underlying issues that need to be addressed. Here are common causes of excessive vibration in a lawn mower and how to troubleshoot and fix them:

  • Blade Imbalance:
    • Blades that are not balanced can cause significant vibration. To fix this issue, remove the blade from the mower and use a blade balancer to check for balance. If imbalanced, it is advisable to replace the blade.
  • Damaged or Bent Blade:
    • Inspect the blade for any signs of damage or bending. A damaged blade can cause the mower to vibrate excessively during operation. Replace the blade if necessary to resolve the issue.
  • Loose Blade:
    • A loose blade can also contribute to vibration. Ensure that the blade is securely fastened to the mower deck according to the manufacturer’s specifications. Tighten any loose bolts or nuts to stabilize the blade.
  • Worn Out Pulleys or Mandrels:
    • Check the pulleys and mandrels for wear and tear. Worn-out components can cause the mower deck to vibrate excessively. Replace any damaged pulleys or mandrels to reduce vibration.
  • Engine Mounts:
    • Inspect the engine mounts to ensure they are secure and in good condition. Loose or deteriorated engine mounts can lead to increased vibration. Replace any defective engine mounts to correct the issue.

By addressing these common causes of excessive vibration in a lawn mower, you can improve the overall performance and operation of the machine, while also ensuring a more comfortable experience for the user.

4. Uneven Cutting Height

Uneven cutting height is a common issue that can result in an unsightly lawn. Here are some steps to address this problem:

  • Check the Mower Deck: Ensure the mower deck is level. Use a leveling tool to adjust the deck if needed.
  • Inspect the Blades: Worn or damaged blades can cause uneven cutting. Sharpen or replace blades as necessary.
  • Tire Pressure: Uneven tire pressure can lead to an uneven cut. Check and adjust the pressure in all tires.
  • Check for Debris: Remove any debris such as rocks or branches from the cutting path that could be causing the mower to cut unevenly.
  • Mow in Overlapping Rows: To ensure an even cut, mow in overlapping rows, especially when dealing with tall or thick grass.

Addressing these factors can help in achieving a more uniform and attractive lawn appearance.

5. Failing Self-Propel System

Self-propelled lawn mowers are designed to make mowing easier by reducing the effort required to push the mower. However, if the self-propel system is failing, it can make the task much more challenging. Here are common issues with self-propel systems and how to fix them:

  • Worn-out Drive Belt: Over time, the drive belt on a self-propelled lawn mower can wear out or break. To fix this issue, you will need to replace the drive belt. Consult your mower’s manual for specific instructions on how to replace the drive belt.
  • Faulty Drive Cable: If the self-propel system is not engaging when you squeeze the drive handle, the drive cable may be faulty. Inspect the drive cable for any signs of damage or wear. Replace the drive cable if necessary following the manufacturer’s instructions.
  • Slipping Drive Wheels: If the drive wheels are slipping or not providing enough traction, it can be due to worn-out treads or a lack of proper lubrication. Check the drive wheels for any signs of wear and replace them if needed. Lubricate the wheels according to the manufacturer’s recommendations.
  • Broken Drive Gear: The drive gear is responsible for transferring power from the engine to the wheels. If the drive gear is broken or damaged, the self-propel system will not function correctly. Replacing the drive gear may require professional assistance, so consider taking your mower to a repair shop for this issue.
  • Solenoid Problems: Some self-propel mowers have a solenoid that controls the engagement of the self-propel system. If the solenoid is faulty, it can prevent the self-propel system from working. Test the solenoid to see if it is functioning correctly and replace it if necessary.

By addressing these common issues with the self-propel system, you can ensure that your lawn mower operates smoothly and makes your mowing tasks more manageable. Regular maintenance and timely repairs can help prolong the life of your mower and keep it in top condition.

6. Clogged Air Filter

A clogged air filter can restrict airflow to the engine, causing starting issues and poor performance. To address this common issue, follow these steps:

  • Locate the Air Filter: The air filter is usually located on the side of the engine or under a cover. Refer to your mower’s manual for specific instructions.
  • Remove the Air Filter: Take out the air filter from its housing. Inspect the filter for dirt, debris, or damage.
  • Clean or Replace the Air Filter: If the air filter is dirty, try cleaning it. You can use compressed air, tap it to remove excess debris, or wash it with soapy water. Let it air dry completely before reinserting. If the filter is damaged or very dirty, it’s best to replace it with a new one.
  • Reinstall the Air Filter: Once the air filter is clean or replaced, carefully place it back in its housing.
  • Test the Lawn Mower: Start your mower and observe if it runs smoothly. Proper airflow can significantly impact the engine performance.

Regularly checking and cleaning or replacing the air filter is essential for maintaining your lawn mower’s efficiency. By keeping the air filter clean, you ensure that your engine receives adequate airflow, leading to better performance and prolonged engine life.

7. Spark Plug Issues

A faulty spark plug can cause your lawn mower to run rough, be hard to start, or even fail to start altogether. Here are some common spark plug issues and how to fix them:

  • Fouled Spark Plug: If the spark plug is covered in black soot or carbon deposits, it is fouled and may need to be cleaned or replaced. To clean it, remove the spark plug and use a wire brush or spark plug cleaner to carefully remove the deposits.
  • Worn Electrodes: Over time, the electrodes on the spark plug can wear down, leading to poor spark production. If the electrodes are worn, it’s best to replace the spark plug with a new one to ensure efficient ignition.
  • Improper Gap: The gap between the electrodes on the spark plug is crucial for proper ignition. If the gap is too large or too small, it can affect the performance of your lawn mower. Use a spark plug gap tool to measure and adjust the gap to the manufacturer’s specifications.
  • Corrosion: Corrosion on the spark plug can cause it to malfunction. If there is visible corrosion, gently clean the spark plug with a wire brush and a mixture of water and baking soda. Rinse it thoroughly and allow it to dry before reinstalling it.
  • Loose Spark Plug: A loose spark plug can cause misfiring or loss of power. Check the spark plug to ensure it is tightly secured in the spark plug hole. Use a spark plug wrench to tighten it if necessary.

By addressing these common spark plug issues promptly, you can keep your lawn mower running smoothly and efficiently. Regularly inspecting and maintaining the spark plug will help prevent performance issues and ensure reliable operation of your lawn mower.

8. Fuel System Problems

Fuel system problems are a common issue that can prevent a lawn mower from starting or running smoothly. Here are some common fuel system issues and how to fix them:

  • Dirty Air Filter: A dirty air filter can restrict airflow to the carburetor, affecting the fuel mixture. Replace the air filter regularly to ensure proper engine performance.
  • Clogged Fuel Filter: If the fuel filter is clogged, it can prevent fuel from reaching the carburetor. Replace the fuel filter if your lawn mower is having trouble getting fuel.
  • Old Gasoline: Stale gasoline can cause performance issues in your lawn mower. Drain old gasoline from the tank and refill it with fresh gasoline.
  • Carburetor Problems: Issues with the carburetor, such as clogs or misadjustments, can lead to poor engine performance. Clean the carburetor or have it professionally serviced if needed.
  • Fuel Line Issues: Check for any kinks, cracks, or leaks in the fuel line that may be preventing fuel from reaching the engine. Replace the fuel line if necessary.
  • Fuel Cap: A faulty or loose fuel cap can cause a drop in fuel pressure, affecting engine performance. Make sure the fuel cap is securely tightened.
  • Fuel Pump: Some lawn mowers have fuel pumps that may need to be replaced if they are not delivering fuel properly to the engine.

By addressing these fuel system problems, you can ensure that your lawn mower runs smoothly and efficiently, allowing you to maintain a well-manicured lawn with ease.

9. Blade Maintenance

  • Regular Inspection: Inspect the lawn mower blade regularly for signs of wear and tear, such as chips, nicks, or dullness. A sharp blade is crucial for a clean cut and a healthy lawn.
  • Sharpening the Blade: Sharpen the blade at least once a year or more frequently if needed. A sharp blade reduces stress on the engine and promotes better grass health.
  • Balancing the Blade: After sharpening, ensure the blade is properly balanced. An unbalanced blade can cause excessive vibrations, leading to damage to the mower.
  • Replacing a Damaged Blade: If the blade is severely damaged or bent, it’s better to replace it rather than trying to repair it. Always use the recommended blade for your mower model.
  • Cleaning the Blade: Regularly clean the blade to prevent buildup of grass clippings, dirt, and debris. A clean blade can function more efficiently and extend its lifespan.
  • Safety Precautions: Prior to any blade maintenance, disconnect the spark plug to prevent accidental starting. Wear gloves and eye protection to protect yourself from sharp edges.

To maintain a healthy and well-functioning lawn mower, proper blade maintenance is essential. Regular inspection, sharpening, balancing, and cleaning of the blade can ensure optimal performance and extend the life of your mower.

10. Belt Issues

If your lawn mower is experiencing belt issues, it can result in poor performance or complete failure of the machine. Here are some common belt problems and how to fix them:

  • Worn or damaged belt: Over time, belts can wear out or get damaged due to regular use. To fix this issue, inspect the belt for any visible signs of wear, cracking, or fraying. If you notice any damage, replace the belt with a new one following the manufacturer’s guidelines.
  • Loose belt: A loose belt can lead to slipping, which affects the mower’s ability to cut grass effectively. To resolve this problem, check the belt’s tension by adjusting the pulleys or replacing the belt if it is stretched out.
  • Misaligned belt: If the belt is not aligned correctly on the pulleys, it can cause noise or uneven cutting. To fix this, adjust the belt so that it sits properly on the pulleys and follows the correct path.
  • Belt off track: Sometimes the belt may come off track due to debris or improper installation. In such cases, carefully place the belt back on track by following the routing diagram in the mower’s manual.
  • Improper belt size: Using the wrong size of the belt can cause it to slip or break. Make sure to replace the belt with the correct size recommended by the manufacturer to avoid any further issues.

By addressing belt issues promptly and correctly, you can ensure your lawn mower operates smoothly and efficiently, allowing you to maintain a well-kept lawn without disruptions.

11. Leaking Oil or Gas

When a lawn mower is leaking oil or gas, it can lead to performance issues and pose a safety hazard. Here are some common causes and solutions for leaks:

  • Loose or damaged fittings: Check for loose or damaged fittings in the oil or gas system, such as the oil filter or gas tank cap. Tighten or replace any parts as needed to prevent leaks.
  • Cracked fuel line: Inspect the fuel line for any cracks or signs of wear. Replace the damaged fuel line to stop gas leaks and ensure proper fuel flow.
  • Faulty gaskets: Worn out or faulty gaskets can cause oil or gas leaks. Replace the gaskets in the engine or fuel system to prevent further leakage issues.
  • Overfilled oil tank: Overfilling the oil tank can cause excess pressure and lead to leaks. Make sure to maintain the oil at the recommended level to avoid leaks.
  • Damaged oil seal: A damaged oil seal can result in oil leaks. Replace the oil seal to prevent oil from seeping out of the engine.

Addressing oil or gas leaks promptly is crucial to keep your lawn mower running smoothly and safely. If you are unsure about how to fix the leak, it’s best to consult a professional to avoid any further damage or safety risks.

12. Electrical Problems

When it comes to lawn mower repair, electrical problems can often be a common issue. Here are some electrical problems that may arise and how you can go about fixing them:

  • Dead Battery
    • Make sure the battery is connected properly, clean the terminals, and try charging it. If the battery still doesn’t hold a charge, it may need to be replaced.
  • Faulty Starter
    • Check the starter switch to see if it’s functioning correctly. If the switch is fine, the starter itself may need to be repaired or replaced.
  • Broken Ignition Coil
    • If your lawn mower won’t start, the ignition coil could be the culprit. Test the coil with a multimeter and replace it if necessary.
  • Blown Fuse
    • If your mower suddenly stops working, check the fuse. Replace it with a new one of the same rating if it’s blown.
  • Faulty Solenoid
    • A clicking sound when you turn the key could indicate a faulty solenoid. Test the solenoid with a multimeter and replace it if needed.
  • Worn Spark Plug
    • A worn spark plug can cause starting issues. Check the condition of the plug and replace it if it’s old or damaged.

Remember, when dealing with electrical components, it’s crucial to prioritize safety. Always disconnect the battery before working on any electrical parts to avoid the risk of shock. If you’re not comfortable diagnosing or repairing electrical issues on your own, it’s best to seek help from a professional lawn mower repair service.

13. Problematic Wheels

Lawn mower wheels can often be a source of frustration when they encounter issues. Here are some common problems with lawn mower wheels and how to troubleshoot them:

  • Uneven Cutting: Uneven cutting is often a result of wheels that are unevenly inflated. Ensure that all the wheels are properly inflated to the recommended PSI levels to maintain an even cutting height.
  • Wobbling Wheels: Wobbling wheels can be due to a loose or damaged wheel hub. Check the wheel hub for any signs of damage and tighten any loose bolts to stabilize the wheel.
  • Wheel Slippage: If the wheels keep slipping or have poor traction, it could be due to worn-out treads. Consider replacing the wheels or adding traction strips to improve grip.
  • Stuck Wheels: Wheels that get stuck or have difficulty turning may be caused by debris lodged in the wheel axles. Remove any debris or dirt from the axles and apply lubricant to ensure smooth movement.
  • Broken Wheels: In case of a broken wheel, it will need to be replaced. Make sure to buy the correct size and type of wheel for your lawn mower model.

By addressing these common wheel problems promptly, lawn mower owners can ensure smooth operation and even cutting performance.

14. Troubleshooting Self-Propel System

When experiencing issues with the self-propel system of your lawn mower, it can be frustrating, but there are common problems you can troubleshoot:

  • Check Drive Belt: Ensure the drive belt is properly connected and not worn out. If it appears loose or damaged, it may need to be replaced.
  • Inspect Drive Cable: Examine the drive cable for any kinks, fraying, or disconnection. Adjust or replace the cable if necessary.
  • Examine Drive Wheels: Inspect the drive wheels for any signs of wear or damage. If they are worn out, consider replacing them to restore proper functionality.
  • Review Traction Drive: The traction drive, often located near the wheels, may need adjustment or replacement if the self-propel feature is not working correctly.
  • Verify Transmission: Check the transmission for any issues such as leaks or malfunctions. Proper maintenance or replacement may be required to resolve the problem.

If troubleshooting these components does not solve the self-propel system issue, it may be best to consult a professional lawn mower repair service.

15. Winterizing Your Lawn Mower

When winter approaches, it is crucial to properly winterize your lawn mower to ensure it stays in good condition during the colder months. Here are some essential steps to winterize your lawn mower:

  • Cleaning: Thoroughly clean the lawn mower, removing any grass clippings, dirt, and debris. This prevents corrosion and rust during storage.
  • Oil Change: Drain the old oil and replace it with fresh oil. Used oil contains contaminants that can harm the engine if left sitting for an extended period.
  • Fuel System: Either run the mower until the fuel tank is empty or use a fuel stabilizer to prevent the gasoline from deteriorating and clogging the fuel system.
  • Air Filter: Check and clean or replace the air filter. A clean air filter improves engine performance and fuel efficiency.
  • Spark Plug: Remove the spark plug and inspect it for wear and corrosion. Replace it if necessary to ensure easy starting in the spring.
  • Lubrication: Lubricate moving parts such as cables, levers, and wheels to prevent them from seizing up during storage.
  • Storage: Store your lawn mower in a dry and sheltered area, away from harsh weather conditions. Cover it with a tarp to protect it from dust and moisture.

By following these winterizing steps, you can prolong the life of your lawn mower and ensure it starts up smoothly when the mowing season returns.

16. Taking Care of Your Lawn Mower Battery

  • Make sure to regularly check the battery terminals for any signs of corrosion. Use a mixture of water and baking soda to clean off any corrosion, ensuring a good connection.
  • During winter months, it is advisable to remove the battery from the lawn mower and store it in a cool, dry place to prevent it from freezing.
  • Keep your battery charged throughout the mowing season. If your mower is not in use for an extended period, consider using a battery maintainer to prevent it from losing charge.
  • Inspect the battery for any physical damage or leaks. If you notice any issues, it may be time to replace the battery.
  • Before attempting to jump-start a lawn mower with a dead battery, ensure that the battery is the issue. It’s helpful to test the battery’s voltage with a multimeter to determine if it is the cause of the problem.
  • When replacing the battery, make sure to choose a suitable replacement with the correct specifications for your lawn mower model.
  • Properly dispose of old lawn mower batteries following local regulations. Many auto parts stores or recycling centers accept old batteries for proper recycling.

By following these maintenance tips, you can ensure that your lawn mower battery remains in good condition and ready to power your mower whenever needed.

17. Preventive Maintenance Tips

  • Regularly Change the Oil:
    • Ensure to follow the manufacturer’s recommendations for oil type and frequency of changes to keep the engine running smoothly.
  • Keep the Air Filter Clean:
    • A clean air filter is essential for optimal engine performance. Check and clean or replace the air filter regularly.
  • Inspect and Tighten Fasteners:
    • Vibration during operation can cause bolts and fasteners to come loose. Periodically check and tighten all nuts, bolts, and screws.
  • Sharpen or Replace Blades:
    • Dull blades will tear grass instead of cutting it cleanly. Sharpen or replace blades as needed to ensure a healthy lawn.
  • Check and Adjust Tire Pressure:
    • Proper tire pressure is crucial for maneuverability and traction. Regularly check and adjust tire pressure as per the manufacturer’s recommendations.
  • Clean the Undercarriage:
    • Grass clippings and debris can accumulate under the mower deck, affecting performance. Regularly clean the undercarriage to prevent clogging.
  • Inspect Spark Plugs:
    • Fouled or worn spark plugs can cause starting issues. Inspect and replace spark plugs as needed to maintain smooth operation.
  • Store Properly:
    • Store the lawn mower in a clean, dry area away from the elements. Consider using a cover to protect it from dust and moisture.
  • Follow the Maintenance Schedule:
    • Adhere to the manufacturer’s recommended maintenance schedule. Regular tune-ups and inspections can help prevent major repair issues.

By following these preventive maintenance tips, lawn mower owners can prolong the life of their equipment and ensure a well-maintained yard.

18. Importance of Professional Maintenance

Regular maintenance of a lawn mower is essential to keep it running smoothly and efficiently. Professional maintenance ensures that all parts are functioning correctly and can address any potential issues before they become major repair problems. Here are a few reasons why professional maintenance is crucial for your lawn mower:

  • Extended Lifespan: Regular maintenance by a professional can significantly extend the lifespan of your lawn mower. By ensuring that all parts are well lubricated, clean, and in good working condition, you can prevent premature wear and tear.
  • Optimal Performance: Professional maintenance helps to keep your lawn mower operating at its best performance level. This includes cleaning or replacing air filters, changing oil, sharpening blades, and adjusting belts to ensure smooth and efficient operation.
  • Safety: A well-maintained lawn mower is safer to use. Professional maintenance can identify and address any safety hazards such as loose or damaged parts, reducing the risk of accidents while operating the equipment.
  • Cost-Effective: While professional maintenance may involve some upfront costs, it can save you money in the long run by preventing major repair issues that can be costly to fix. Regular maintenance can help you avoid expensive repairs or even the need to replace the entire lawn mower.
  • Warranty Compliance: Some lawn mower warranties require regular professional maintenance to remain valid. By keeping up with professional maintenance, you can ensure that your warranty coverage remains intact.

In conclusion, investing in professional maintenance for your lawn mower is a smart decision that can help you save money, ensure safety, and prolong the lifespan of your equipment.


  • Keep your lawn mower in top condition by regularly checking and maintaining it.
  • Addressing repair issues promptly can prevent further damage and extend the life of your equipment.
  • Simple troubleshooting steps can often resolve common lawn mower problems without the need for professional help.
  • Regularly cleaning and sharpening blades, checking oil levels, and inspecting spark plugs can prevent many common issues.
  • If you encounter more complex problems, don’t hesitate to seek assistance from a professional repair service.

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