How To Maintain a Gas Lawn Mower

Proper lawn mower maintenance is essential for keeping your grass looking its best all season long. Regular upkeep not only extends the life of your mower but also ensures it runs efficiently, saving you time and money in the long run. In this guide, we walk you through the key steps to maintain your lawn mower, from basic tune-ups to more involved tasks. 

In the video, This Old House landscape contractor Roger Cook and host Kevin O’Connor demonstrate essential maintenance techniques to keep your gas mower running smoothly all summer.

End-of-Season Maintenance for a Gas Mower

Before storing your lawn mower for the winter, it’s crucial to perform some basic maintenance tasks. These steps will help protect your mower during the offseason and ensure it’s ready to go when spring arrives.

Run the Mower Out of Gas

At the end of the mowing season, start your mower and allow it to run until it’s completely out of gas. This practice offers several benefits:

• Helps avoid hard starting issues in the spring.
• Prevents stale gas from sitting in the tank for months.
• Reduces the risk of gumming up the carburetor.

Clean the Mower Deck

After the final mow of the season, you need to perform some maintenance to ensure your mower stays in good condition. This includes the following:

• Allowing the mower to dry completely before storage
• Removing grass clippings and debris from the mower deck
• Spraying the underside of the deck with a hose to remove built-up grass

Store in a Dry Location

Proper storage is important for protecting your mower during the offseason. Do the following:

1. Choose a dry, covered area such as a garage or shed.
2. Elevate the mower off the ground if possible to prevent moisture damage.
3. Cover the mower with a breathable cover to keep dust off while allowing air circulation.

Spring Tune-Up for a Gas Mower

When spring arrives, it’s time to get your lawn mower ready for another season of use. A thorough tune-up will ensure your mower starts easily and runs efficiently.

Change the Oil

Changing the oil is one of the most important maintenance tasks for your lawn mower. Fresh oil helps the engine run smoothly and protects it from wear and tear. Here’s how to change the oil:

1. Disconnect the spark plug wire to prevent accidental starting.
2. Remove the oil fill cap and tilt the mower onto its side to drain the old oil into a pan.
3. Once drained, return the mower to its upright position.
4. Use a funnel to add the correct type and amount of motor oil, as specified by the mower manufacturer.
5. Use the dipstick to confirm the correct oil level, adding more if necessary but being careful not to overfill.

Remember to recycle the old oil at an appropriate facility. Change the oil at least once a year to keep your mower’s performance up to mark.

Replace the Air Filter

A clean air filter is crucial for your mower’s performance. Here’s how to replace it:

1. Locate the air filter cover, typically on the side of the engine.
2. Unscrew the cover and remove the old filter.
3. Insert a new filter of the exact type specified in the owner’s manual.
4. Reattach the air filter cover securely.

Install a New Spark Plug

Replacing the spark plug annually ensures easy starting and efficient operation.

1. Remove the old spark plug using a ratchet wrench and spark plug socket.
2. Take the old plug to the store to ensure you get the same exact size and type.
3. Hand-thread the new spark plug into the engine, being careful not to cross the threads.
4. Once hand-tight, finish tightening with the ratchet wrench.

Inspect and Clean the Mower

A clean mower not only looks good but also operates more efficiently. Here’s how to keep it clean:

• Clean the grass bag to ensure proper airflow.
• Scrub the deck with a brush to get rid of stuck-on debris.
• Use a damp cloth to wipe down the exterior of the machine.

Regular Maintenance Tasks for a Gas Mower

Throughout the mowing season, perform the following tasks to keep your mower in top condition.

Sharpen or Replace the Blade

A sharp blade is essential for a clean cut and a healthy lawn.

Sharpen or replace the blade:

• At the start of each mowing season.
• If the blade becomes damaged or bent.
• Whenever you notice ragged grass tips after mowing.

Clean or Replace the Spark Arrestor

The spark arrestor prevents the engine from emitting sparks. Clean or replace it according to your mower’s manual, typically:

• Every 100 hours of operation
• At least once per mowing season

Lubricate Moving Parts

Proper lubrication reduces wear and ensures smooth operation. Here’s how to do it:

• Apply a light coating of spray lubricant to both wheel axles.
• Lubricate control cables as specified in your mower’s manual.
• Oil any other moving parts as recommended by the manufacturer.

Check Tire Pressure and Wheels

To ensure an even cut and smooth ride:

• Check tire pressure and adjust as needed.
• Inspect wheels for wear and tear.
• Make sure the wheel nuts are tight.

Examine the Fuel System

The fuel system needs periodic checks during the mowing season. You can do do this by:

• Checking for leaks or corrosion
• Ensuring the fuel lines are intact
• Replacing the fuel filter if clogged

Troubleshooting Common Issues for Gas Mowers

Even with regular maintenance, you may encounter some common lawn mower problems. Here’s how to address them.

Mower Won’t Start

If your mower won’t start, do the following:

• Check that the spark plug wire is securely connected.
• Confirm the oil level is correct.
• Ensure there’s fresh fuel in the tank.
• Verify that the air filter isn’t clogged.

Uneven Cutting

If it’s cutting unevenly, consider doing the following:

• Checking that all wheels are the same height
• Ensuring the mower deck is clean and free of debris
• Inspecting the blade for damage or dullness

Excessive Vibration

If you notice unusual vibrations while mowing:

• Examine the blade for balance issues or damage.
• Check for loose bolts or parts.
• Inspect the crankshaft for bending (a sign of more serious damage).

Engine Overheating

An overheating engine can be problematic. You can remedy this by:

• Cleaning the air filter to maintain airflow
• Ensuring proper ventilation by cleaning the engine fins
• Verifying the oil level and type

Our Conclusion

Regular lawn mower maintenance is key to keeping your mower running efficiently and your lawn looking its best. By following these steps for end-of-season care, spring tune-ups, and ongoing maintenance, you’ll extend the life of your mower and ensure it’s ready to tackle your lawn care needs year after year.