The warm weather has finally arrived, and you’re eager to get your lawn looking its best. But when you pull the cord on your trusty lawn mower, all you hear is a frustrating silence. The dreaded “won’t start” syndrome has struck again. Don’t worry, this article will guide you through the most common culprits and offer troubleshooting tips to get your mower roaring back to life.
A lawn mower failing to start can be attributed to a variety of reasons, ranging from simple fuel issues to more complex electrical problems. We will cover the most common causes and how to address them, from checking for spark and fuel delivery to identifying issues with the starting mechanism and engine components. By the time you finish reading, you’ll be equipped to diagnose and tackle most common lawn mower starting problems.
Fuel System Troubles
The first place to start your investigation is the fuel system, as it’s the most common culprit for a non-starting mower.
1. Fuel Issues
a) Old Gas
Gasoline degrades over time, losing its volatility and ability to ignite properly. This can lead to a stubborn mower that refuses to start.
- Solution: If your mower has been sitting for a while, it’s best to drain the old gas and replace it with fresh, high-octane fuel.
b) Empty Gas Tank
This might seem obvious, but it’s often overlooked!
- Solution: Check the gas gauge or simply glance at the fuel level in the tank. If it’s empty, fill it up and try starting the mower again.
c) Clogged Fuel Lines or Filter
Over time, dirt and debris can accumulate in the fuel lines or filter, obstructing fuel flow to the engine.
- Solution: Inspect the fuel lines and filter for any blockages or damage. Clean or replace them as necessary.
2. Carburetor Problems
The carburetor is responsible for mixing fuel and air before it enters the engine. Several issues can arise in this crucial component.
a) Dirty Carburetor
Dirt, debris, and gum deposits can clog the carburetor jets, hindering fuel delivery.
- Solution: A thorough cleaning with carburetor cleaner is usually enough to remedy the situation. Consult your owner’s manual for detailed instructions.
b) Carburetor Adjustment
The carburetor needs to be properly adjusted to achieve the correct fuel-to-air ratio. Incorrect settings can lead to a difficult start.
- Solution: Refer to your owner’s manual or a professional for guidance on adjusting the carburetor settings. Improper adjustments can damage the engine.
Ignition System Malfunctions
The ignition system is responsible for creating the spark that ignites the fuel-air mixture in the engine cylinder. When it’s not working correctly, your mower won’t start.
1. Spark Plug Issues
a) Fouled Spark Plug
A spark plug can become fouled by oil, carbon, or fuel deposits, preventing it from generating a spark.
- Solution: Remove the spark plug, inspect it for signs of fouling, and clean or replace it as needed.
b) Worn-Out Spark Plug
Over time, spark plugs wear out and their ability to generate a spark weakens.
- Solution: Replace a worn-out spark plug with a new one of the correct type and gap.
2. Ignition Coil Issues
The ignition coil transforms low-voltage battery power into the high-voltage electricity needed for the spark plug.
a) Faulty Ignition Coil
A damaged or malfunctioning ignition coil can prevent the spark from reaching the spark plug.
- Solution: Check the ignition coil for signs of damage, such as cracks or burns. If it appears faulty, replace it with a new one.
3. Spark Plug Wire Issues
The spark plug wire connects the ignition coil to the spark plug.
a) Damaged or Loose Wire
A damaged or loose wire can interrupt the electrical connection, preventing a spark from reaching the plug.
- Solution: Inspect the wire for any cuts, cracks, or loose connections. Repair or replace the wire if necessary.
Starting Mechanism Troubles
The starting mechanism is responsible for engaging the engine crankshaft, allowing it to turn and start.
1. Recoil Starter Issues
The recoil starter uses a spring and a cable to turn the crankshaft.
a) Broken Spring or Cable
A broken spring or cable will prevent the starter from engaging the crankshaft.
- Solution: Replace the broken spring or cable with a new one.
b) Stuck Starter
The starter can become stuck due to debris or wear.
- Solution: Clean the starter mechanism and lubricate any moving parts. If it remains stuck, you may need to replace the entire starter assembly.
2. Battery Problems (Electric Start Mowers)
Electric start mowers rely on a battery to power the starter motor.
a) Dead Battery
A dead battery will prevent the starter motor from turning the crankshaft.
- Solution: Check the battery voltage and charge it or replace it if necessary.
b) Faulty Battery Cables
Loose or corroded battery cables can interrupt the electrical connection to the starter motor.
- Solution: Clean the battery terminals and tighten the cables. If the cables are damaged, replace them.
Engine Problems
1. Engine Compression
Low engine compression can make it difficult to start the mower.
a) Worn Piston Rings
Worn piston rings allow compression to escape, reducing the engine’s ability to start.
- Solution: This problem typically requires a major engine rebuild.
b) Valve Problems
Stuck or leaking valves can also cause low compression.
- Solution: This problem may require valve adjustment or replacement.
2. Engine Oil Level
The engine needs enough oil to lubricate moving parts.
a) Low Oil Level
A low oil level can cause damage and prevent the engine from starting.
- Solution: Check the oil level and add oil if necessary. Never run the engine without enough oil.
Other Possible Causes
- Fuel Shutoff Valve: Make sure the fuel shutoff valve is open.
- Air Filter: A clogged air filter restricts air flow to the engine, making it difficult to start. Clean or replace the air filter.
- Choke: The choke helps enrich the fuel-air mixture for easier starting, especially in cold weather. Ensure the choke is properly engaged for cold starts.
- Environmental Factors: Extreme temperatures can affect engine performance. If it’s very cold or very hot, starting the mower may be more difficult.
When to Seek Professional Help
While many starting problems can be tackled by yourself, some situations warrant professional assistance. If you’ve checked the common culprits and your mower still won’t start, it’s best to seek the advice of a qualified mechanic.
- Advanced Engine Problems: If you suspect a serious engine problem, like a blown head gasket or a damaged crankshaft, it’s crucial to have a professional diagnose and repair the issue.
- Electrical Problems: If you’re not comfortable working with electrical systems, it’s best to leave complex wiring issues to a qualified technician.
- Carburetor Adjustment: Adjusting the carburetor incorrectly can damage the engine. If you’re unsure about carburetor settings, seek professional help.
By following these troubleshooting tips, you can diagnose and fix most common lawn mower starting issues. Remember to exercise caution when working with fuel and electrical systems, and always consult your owner’s manual for specific instructions on your mower model.
FAQs
Q1: I just filled the gas tank, but my lawnmower won’t start. What could be the problem?
A: While it seems obvious, make sure you’re using fresh gasoline. Old gas can go bad and clog the carburetor, making it difficult to start the engine. Also, check the fuel lines for any cracks or leaks. If you find any, it’s best to replace them to avoid further issues.
Q2: My lawnmower is getting spark but still won’t start. What should I do?
A: If your lawnmower is sparking but not starting, it could be a problem with the carburetor. The carburetor mixes air and fuel, and if it’s clogged or misadjusted, it can prevent the engine from getting the proper mixture to start. You can try cleaning the carburetor yourself or take it to a repair shop for professional cleaning.
Q3: I can hear the engine trying to start, but it’s not catching. What’s the problem?
A: If you hear the engine cranking but not starting, it’s likely an issue with the air filter. A dirty air filter restricts airflow to the engine, making it difficult to start. Remove and clean the air filter, or replace it with a new one if it’s beyond cleaning.
Q4: My lawnmower’s battery is dead. How do I fix this?
A: If your lawnmower has a battery, it’s likely dead if it won’t start. To fix this, you can either jump-start the battery using another battery or replace it with a new one. If you choose to jump-start it, make sure the battery terminals are properly connected.
Q5: I’m getting a weak spark. What should I do?
A: A weak spark can be caused by a faulty spark plug, a dirty spark plug wire, or a problem with the ignition coil. First, check the spark plug for wear and tear and replace it if necessary. Then, inspect the spark plug wire for any cracks or damage and replace it if needed. If you suspect an issue with the ignition coil, it’s best to consult a repair shop for professional diagnosis and repair.
Q6: The engine is flooded. How do I fix this?
A: If your engine is flooded, it means it has too much fuel. To fix this, remove the spark plug and crank the engine several times to clear out excess fuel. Once the engine starts to sound like it’s turning over normally, reinstall the spark plug and try starting it again.
Q7: My lawnmower won’t start even after trying all these solutions. What do I do?
A: If you’ve tried all of these solutions and your lawnmower still won’t start, it’s best to take it to a repair shop. A professional technician can diagnose the problem and perform the necessary repairs to get your lawnmower running smoothly again.