The sun is shining, the birds are chirping, and your yard is begging for a trim. You pull out your trusty lawn mower, only to find it won’t start. The familiar rumble of the engine is replaced by a frustrating silence. Don’t worry! A lawn mower that’s been sitting idle for a while can be a bit cranky, but with a little troubleshooting and know-how, you can get it back in working order and have your lawn looking pristine in no time.
This article will guide you through the most common reasons your lawn mower won’t start after sitting and equip you with the tools and knowledge to get it roaring back to life. We’ll cover everything from the basics of fuel and spark to more advanced troubleshooting techniques.
Here’s a quick overview of what we’ll be covering:
- Understanding the Basics – We’ll start with the fundamental components that need to work together for your lawn mower to fire up.
- Troubleshooting Common Issues – We’ll delve into the most frequent problems encountered when trying to start a dormant lawn mower.
- Step-by-Step Solutions – Learn practical solutions and detailed instructions to address each issue.
- Preventing Future Problems – Discover tips and tricks for keeping your lawn mower running smoothly and avoiding future start-up troubles.
Understanding the Basics: What Makes a Lawn Mower Go?
To understand why your lawn mower isn’t starting, you need to grasp the basic principles of how it operates. Essentially, a lawn mower is a small engine that uses a few key components to work:
- Fuel: The engine needs fuel to burn and create power.
- Spark: A spark plug ignites the fuel mixture, creating an explosion that drives the engine.
- Air: The engine needs oxygen from the air to help the fuel burn properly.
- Compression: The piston within the engine creates pressure that helps compress the fuel-air mixture.
If any of these components are not working correctly, your lawn mower won’t start.
Troubleshooting Common Issues: A Diagnostic Checklist
Now that you understand the basics, let’s dive into the common culprits that prevent a lawn mower from starting after sitting:
1. Old Fuel: The Most Common Culprit
One of the most frequent reasons for a stubborn lawn mower is old, stale fuel. Here’s why:
- Fuel Breakdown: Gasoline is a volatile liquid that degrades over time, especially when exposed to air and sunlight.
- Gum and Varnish: As fuel ages, it can form gum and varnish deposits within the fuel system, clogging lines and hindering the flow of fuel to the engine.
- Difficulty Starting: These deposits can prevent the engine from receiving the fuel it needs to start.
What to Do:
- Drain the Old Fuel: The first step is to drain the old fuel from the tank. Use a siphon pump or a clean container to carefully remove the fuel from the tank.
- Fill with Fresh Fuel: Once the old fuel is out, fill the tank with fresh, high-quality gasoline.
- Add Fuel Stabilizer: For long-term storage, consider adding a fuel stabilizer to your fresh fuel. This helps prevent the fuel from degrading and causing issues in the future.
2. Spark Plug Problems: A Crucial Connection
The spark plug plays a vital role in igniting the fuel mixture. If it’s not working correctly, your lawn mower won’t fire up.
Common Spark Plug Issues:
- Foul Spark Plug: The spark plug can become fouled with carbon deposits or oil, preventing a strong spark.
- Worn Spark Plug: Over time, spark plugs wear down and can lose their ability to generate a spark.
What to Do:
- Inspect the Spark Plug: Remove the spark plug and inspect it. Look for signs of fouling (black soot, oil deposits) or wear (excessive gap, electrode erosion).
- Replace if Necessary: If the spark plug is fouled or worn, replace it with a new one of the correct type for your lawn mower.
- Check the Spark Gap: Ensure the spark plug gap is set to the manufacturer’s specification.
3. Dirty Air Filter: Choking the Engine
The air filter is crucial for providing clean air to the engine. A clogged or dirty air filter restricts airflow and can make it difficult to start the mower.
What to Do:
- Remove the Air Filter: Locate the air filter and remove it. Inspect it for dirt, debris, and blockages.
- Clean or Replace: If the filter is dirty, clean it with compressed air or replace it with a new one.
4. Clogged Fuel Lines: A Silent Blockage
Sometimes, fuel lines can become clogged with debris, varnish, or dirt, hindering fuel flow to the engine.
What to Do:
- Check for Obstructions: Visually inspect the fuel lines for any visible blockages.
- Clear Obstructions: If you find any debris, carefully remove it. For more stubborn clogs, consider using a fuel line cleaning solution.
- Replace if Necessary: If the fuel lines are severely damaged or clogged, they may need to be replaced.
5. Engine Oil Problems: Lubrication is Key
The engine oil lubricates the moving parts and helps dissipate heat. Low or dirty oil can cause issues with starting and overall engine performance.
What to Do:
- Check the Oil Level: Ensure the oil level is within the recommended range.
- Change the Oil: If the oil is dirty or has been in the engine for a long time, change it with fresh oil.
Step-by-Step Solutions: Bringing Your Lawn Mower Back to Life
Now, let’s put your troubleshooting skills to work and walk through the most effective ways to get your lawn mower running again:
1. Fuel-Related Problems
a. Draining the Old Fuel
- Locate the Fuel Tank: Find the fuel tank on your lawn mower.
- Remove the Fuel Cap: Unscrew the fuel cap to release any pressure.
- Prepare a Container: Have a clean container ready to collect the old fuel.
- Use a Siphon: If you have a siphon pump, carefully lower it into the tank and use it to draw out the old fuel.
- If No Siphon: If you don’t have a siphon, carefully tilt the tank and slowly pour the fuel out. Be sure to do this over a safe area and avoid spilling.
- Empty the Fuel Line: Once the tank is empty, locate the fuel line and carefully remove it from the carburetor.
- Clean the Fuel Line: Remove any debris or clogs from the fuel line.
- Refill the Tank: Refill the tank with fresh, high-quality gasoline.
- Reconnect the Fuel Line: Reattach the fuel line to the carburetor.
b. Cleaning the Fuel System
- Use a Fuel Line Cleaning Solution: Pour a fuel line cleaning solution into the tank (follow the instructions on the bottle).
- Run the Engine Briefly: Start the engine and let it run for a few minutes to circulate the cleaning solution.
- Drain and Refuel: Drain the tank again and refill it with fresh gasoline.
2. Spark Plug Problems
- Locate the Spark Plug: Find the spark plug on the engine. It’s usually located near the cylinder head.
- Remove the Spark Plug: Use a spark plug socket wrench to remove the spark plug.
- Inspect the Spark Plug: Check the spark plug for signs of fouling (black soot, oil deposits) or wear (excessive gap, electrode erosion).
- Replace if Necessary: If the spark plug is fouled or worn, replace it with a new one. Ensure the new spark plug is the correct type for your lawn mower.
- Set the Spark Gap: Use a spark plug gap tool to adjust the gap to the manufacturer’s specifications.
- Reinstall the Spark Plug: Carefully screw the spark plug back into the cylinder head.
3. Dirty Air Filter
- Locate the Air Filter: Find the air filter housing, usually located on the side or top of the engine.
- Remove the Air Filter: Remove the air filter cover and carefully pull out the air filter.
- Inspect the Air Filter: Check for dirt, debris, or any blockage.
- Clean or Replace: If the filter is dirty, clean it with compressed air or replace it with a new one.
- Reinstall the Air Filter: Replace the air filter and secure the air filter cover.
4. Clogged Fuel Lines
- Inspect the Fuel Lines: Visually examine the fuel lines for any visible clogs or blockages.
- Clear Obstructions: If you find any debris, carefully remove it. For stubborn clogs, consider using a fuel line cleaning solution.
- Replace if Necessary: If the fuel lines are damaged or severely clogged, they may need to be replaced.
5. Engine Oil Problems
- Check the Oil Level: Locate the dipstick on the engine and pull it out. Wipe it clean and insert it back into the dipstick tube. Pull it out again and check the oil level.
- Add Oil if Needed: If the oil level is low, add the correct type and amount of engine oil.
- Change the Oil: If the oil is dirty or has been in the engine for a long time, change it with fresh oil.
Preventing Future Problems: Maintaining Your Mower
Taking preventative measures can keep your lawn mower running smoothly and minimize the chances of future start-up problems:
- Store Your Mower Properly: When not in use, store your mower in a dry, clean, and well-ventilated area.
- Use Fresh Fuel: Always use fresh, high-quality gasoline.
- Add Fuel Stabilizer: If you plan to store your mower for an extended period, add a fuel stabilizer to prevent fuel degradation.
- Clean the Air Filter Regularly: Check and clean the air filter regularly to ensure proper airflow.
- Change the Oil Regularly: Change the engine oil according to the manufacturer’s recommendations.
Remember: It’s always best to consult your lawn mower’s manual for specific instructions and maintenance schedules.
By understanding the basics of lawn mower operation, identifying common issues, and applying the right solutions, you can easily conquer those stubborn starts and have your lawn looking pristine all season long.
FAQ
Why won’t my lawn mower start after sitting?
There are a few reasons why your lawn mower might not start after sitting for a while. The most common reason is that the fuel has gone bad. Gasoline can degrade over time, especially if it’s been sitting in the tank for a long time. This can cause the fuel to become gummy and clog the carburetor. Other reasons include a dead battery, a clogged air filter, or a dirty spark plug.
To troubleshoot the problem, you’ll need to check the fuel, the battery, the air filter, and the spark plug. If you find that the fuel is bad, you’ll need to drain it and replace it with fresh fuel. If the battery is dead, you’ll need to charge it or replace it. If the air filter is clogged, you’ll need to clean or replace it. And if the spark plug is dirty, you’ll need to clean or replace it.
How do I start a lawn mower after it’s been sitting for a long time?
The first step is to check the fuel. If the fuel is old, you’ll need to drain it and replace it with fresh fuel. If the fuel is new, you can try to start the mower by following these steps:
- Make sure the choke is engaged. This will help the engine get started.
- Pull the starter cord slowly at first, then give it a few sharp pulls.
- Once the engine starts, release the choke slowly.
- If the engine doesn’t start after a few tries, you may need to check the spark plug, air filter, and battery.
What if the fuel is old?
If the fuel in your lawn mower is old, it’s best to drain it and replace it with fresh fuel. Old fuel can cause problems with the carburetor, which can make it difficult to start the mower. To drain the fuel, simply remove the fuel cap and tilt the mower so that the fuel flows out of the tank.
Once the tank is empty, you can refill it with fresh fuel. You should also add a fuel stabilizer to the new fuel to help prevent it from going bad.
How do I check the spark plug?
The spark plug is a key component in the ignition system of your lawn mower. To check it, you’ll need to remove it from the engine. Once you’ve removed the spark plug, you can inspect it for signs of wear and tear. The spark plug should be clean and free of carbon buildup. If the spark plug is dirty or worn out, you’ll need to replace it.
To test the spark plug, you can hold it against a metal surface and ground the wire to the metal. Then, pull the starter cord. If there is a spark, the spark plug is working properly. If there is no spark, you’ll need to replace the spark plug.
What if the air filter is clogged?
A clogged air filter can restrict airflow to the engine, making it difficult to start. To check the air filter, you’ll need to remove it from the mower. Once you’ve removed the air filter, you can inspect it for signs of dirt and debris. If the air filter is dirty, you’ll need to clean or replace it.
To clean the air filter, you can use a vacuum cleaner or compressed air. If the air filter is too dirty to clean, you’ll need to replace it.
What if the battery is dead?
A dead battery can prevent your lawn mower from starting. To check the battery, you can use a voltmeter. If the battery voltage is below 12 volts, you’ll need to charge it or replace it.
To charge the battery, you can use a battery charger. To replace the battery, you’ll need to purchase a new battery that is compatible with your lawn mower.
What are some preventative measures I can take?
To prevent your lawn mower from sitting for too long, you can try to use it regularly. If you don’t plan on using your lawn mower for a while, you should drain the fuel tank and add a fuel stabilizer to the fresh fuel. This will help to prevent the fuel from going bad.
You can also store your lawn mower in a dry, clean place. This will help to prevent the engine from rusting and the battery from corroding. Finally, you should check the spark plug, air filter, and battery regularly to make sure they are in good working order.