The feeling is familiar: you grab your trusty lawn mower, pull the cord, and – success! The engine roars to life. You give it a moment to warm up, then start to mow. But just a few seconds later, the engine sputters and dies. Frustration sets in – why won’t your mower stay running?
This common problem can be caused by a variety of factors, from simple fuel issues to more complex engine problems. This article will guide you through the most likely culprits, explaining how to troubleshoot each one and get your mower back in working order. We’ll cover everything from fuel and air intake problems to spark plug issues and even electrical malfunctions. By the end, you’ll have the knowledge to diagnose the problem and fix your mower, saving you time and money on expensive repairs.
A Brief Overview
When your lawn mower starts then dies, it usually indicates a problem with the fuel system, the ignition system, or the air intake system. The fuel system needs to deliver a consistent supply of fuel to the engine, while the ignition system needs to spark the fuel-air mixture. Finally, the air intake system needs to supply the right amount of air for combustion. If any of these systems malfunction, the engine won’t be able to run properly.
Fuel System Problems
The fuel system is the most common culprit when a lawn mower starts and dies. Here’s why:
1. Old or Bad Gas
Fuel deteriorates over time, becoming gummy and unusable. This can clog the fuel lines and carburetor, preventing fuel from reaching the engine.
- Solution: Empty the old fuel and refill the tank with fresh, high-octane gasoline.
2. Clogged Fuel Filter
The fuel filter traps debris and prevents it from entering the engine. If the filter becomes clogged, fuel flow will be restricted.
- Solution: Replace the fuel filter. You can find replacement filters at most hardware stores.
3. Dirty Carburetor
The carburetor mixes air and fuel for combustion. Over time, it can become clogged with debris or varnish, disrupting the fuel-air mixture.
- Solution: Clean the carburetor thoroughly. You’ll need a carburetor cleaning kit and some patience. Follow the manufacturer’s instructions for your specific model.
How to Clean a Carburetor
Step 1: Disconnect the fuel line and remove the carburetor.
Step 2: Soak the carburetor in a carburetor cleaner.
Step 3: Use a small brush and compressed air to clean out any debris.
Step 4: Reassemble the carburetor and reconnect the fuel line.
4. Fuel Line Issues
Cracked or kinked fuel lines can restrict fuel flow to the carburetor.
- Solution: Inspect the fuel lines for cracks or kinks. If you find any, replace the line.
Ignition System Problems
The ignition system is responsible for creating a spark that ignites the fuel-air mixture. If there’s a problem with the ignition system, the engine won’t fire.
1. Faulty Spark Plug
The spark plug delivers the spark that ignites the fuel. Over time, the spark plug can wear out or become fouled with carbon deposits. A faulty spark plug will prevent the engine from starting or running smoothly.
- Solution: Replace the spark plug. Make sure to use the correct spark plug for your lawn mower model.
2. Worn Spark Plug Wires
The spark plug wires carry the electrical current from the ignition coil to the spark plug. If the wires are worn or cracked, they can create a weak spark or no spark at all.
- Solution: Inspect the spark plug wires for wear or cracks. If you find any, replace the wires.
3. Faulty Ignition Coil
The ignition coil generates the high voltage needed to create a spark. A faulty ignition coil can prevent the spark plug from firing.
- Solution: Replace the ignition coil.
Air Intake System Problems
The air intake system delivers air to the engine for combustion. If the air intake is blocked, the engine won’t get enough air and will sputter and die.
1. Clogged Air Filter
The air filter traps debris and prevents it from entering the engine. If the filter becomes clogged, it restricts airflow to the engine.
- Solution: Replace the air filter.
2. Blocked Air Intake
The air intake is the opening that allows air to enter the engine. If the intake is blocked, it will restrict airflow to the engine.
- Solution: Clean the air intake. Make sure to remove any debris or obstructions.
3. Fuel in the Air Intake
If there is fuel leaking from the carburetor, it could be entering the air intake and blocking airflow.
- Solution: Clean the air intake. Replace the carburetor if necessary.
Other Potential Problems
While less common, there are other potential causes for your lawn mower starting then dying:
1. Low Oil Level
If the oil level is too low, it can cause damage to the engine, which could lead to it starting and then dying.
- Solution: Check the oil level and add oil if needed.
2. Electrical Malfunction
A problem with the ignition switch, wiring, or battery can prevent the engine from starting or running.
- Solution: Inspect the electrical components for signs of damage or corrosion. Replace any faulty components.
3. Engine Problems
In some cases, the engine itself may be damaged, requiring more extensive repairs.
- Solution: If you suspect an engine problem, you should take your lawn mower to a qualified mechanic.
Conclusion
Your lawn mower starting then dying is a common problem with a range of potential causes. By following the troubleshooting steps outlined in this article, you can identify the problem and make the necessary repairs. Remember to start with the simplest solutions first, such as checking the fuel, spark plug, and air filter. If you’re still having trouble, consult a qualified mechanic.
With a little patience and effort, you’ll be able to get your lawn mower back in shape and ready for the next mowing season.
Frequently Asked Questions
1. Why is my lawn mower starting then dying immediately?
The most common reason for a lawn mower starting then dying immediately is a lack of fuel. Make sure your gas tank has fuel and that the fuel line is connected properly. If you haven’t used the mower in a while, the fuel may have gone bad. Try draining the old fuel and adding fresh, high-quality gasoline. If this doesn’t fix the problem, there may be a blockage in the fuel line or carburetor.
If you’ve recently changed the spark plug, there’s a chance it wasn’t installed correctly. Double-check the spark plug’s connection and gap. If you suspect a faulty spark plug, try replacing it with a new one.
2. Why is my lawn mower starting then dying after a few minutes?
A common cause for this issue is a clogged air filter. When the air filter is dirty, it restricts airflow to the engine, causing it to run poorly and eventually stall. Check the air filter and replace it if it’s dirty. Another possibility is a faulty fuel pump. A malfunctioning fuel pump may not be able to deliver enough fuel to keep the engine running. You can test the fuel pump by checking for fuel pressure at the fuel line.
If the problem persists, a clogged carburetor is a likely culprit. This can happen due to dirty fuel or debris entering the carburetor. You can try cleaning the carburetor yourself or take it to a professional mechanic for cleaning.
3. Why is my lawn mower starting then dying when I try to accelerate it?
A common reason for this is a faulty carburetor. A dirty or malfunctioning carburetor can prevent the engine from receiving enough fuel when you accelerate. Cleaning or replacing the carburetor may resolve this problem.
Another possibility is a clogged fuel filter. A clogged fuel filter restricts fuel flow to the engine, causing it to run poorly and stall under load. You can inspect and clean or replace the fuel filter if necessary.
4. Why is my lawn mower starting then dying when it’s hot?
If your lawnmower starts and runs normally when cold but stalls when it heats up, the issue might be related to the ignition system. The problem could be a faulty spark plug, ignition coil, or a loose wire connection. Inspect each component carefully and replace any faulty parts.
Another potential culprit is a fuel line that is getting clogged by debris or varnish buildup as it heats up. Examine the fuel lines and replace any damaged or brittle parts.
5. Why is my lawn mower starting then dying after I mow for a while?
This issue is often related to the cooling system. If the mower is overheating, it can cause it to stall. First, check the engine oil level to ensure it’s sufficient. Then, inspect the cooling fins for any blockage or debris. A faulty cooling fan may also be the problem.
If the cooling system seems fine, the engine may be running too lean, meaning it’s not getting enough fuel. This can happen due to a carburetor problem or a faulty fuel line. Check for any leaks or blockages in the fuel system and adjust the carburetor settings as needed.
6. What are some general troubleshooting steps for a lawn mower that starts then dies?
Start by checking the fuel system. Ensure the gas tank is full, the fuel is fresh, and the fuel lines are clear. Then, inspect the air filter and replace it if it’s dirty. Next, check the spark plug for damage or wear. Finally, ensure the spark plug wire is securely connected.
If these basic checks don’t solve the problem, you may need to investigate more complex issues like a faulty carburetor or ignition system. Consulting a mechanic is always a good idea if you’re unsure about troubleshooting your lawn mower.
7. What are some common maintenance tips to prevent lawn mower starting then dying issues?
Regular maintenance is crucial for keeping your lawn mower running smoothly. Change the engine oil and air filter regularly, according to the manufacturer’s recommendations. Inspect the spark plug and replace it if it’s worn or damaged. Clean the carburetor annually to prevent buildup.
Finally, always use fresh, high-quality gasoline and store your lawn mower properly during the off-season. By following these tips, you can minimize the chances of encountering starting and dying problems.