The warm sun is shining, the grass is growing, and you’re ready to tackle your lawn. But when you go to start your trusty riding mower, it just sits there, silent and unmoving. What could be wrong? This frustrating experience is all too common for many lawn mower owners. This article will delve into the most common causes behind a non-starting riding lawn mower, giving you the knowledge to troubleshoot the problem and get back to mowing in no time. We’ll explore everything from basic checks like fuel and battery to more complex issues like ignition problems and carburetor troubles.
Why Won’t My Riding Lawn Mower Start?
A riding lawn mower that refuses to start can be caused by a variety of factors. It’s important to approach troubleshooting systematically, starting with the simplest and most likely culprits. The most common causes include:
- Lack of fuel or a fuel problem: The mower might not have enough fuel, the fuel might be old or contaminated, or the fuel line may be clogged.
- Battery issues: A dead or weak battery can prevent the mower from starting.
- Ignition problems: The spark plugs, ignition coil, or wiring may be faulty.
- Carburetor problems: A clogged or malfunctioning carburetor can prevent fuel from reaching the engine.
- Engine issues: The engine may be flooded, have low compression, or have a mechanical problem.
Fuel-Related Problems:
Before you even consider more complex issues, make sure the lawn mower has fuel and that the fuel is fresh and usable.
1. Check the Fuel Level
The most obvious reason your lawn mower won’t start is that it’s simply out of fuel. Take a moment to check the fuel tank. If the tank is empty, simply add fresh gasoline.
2. Check the Fuel Quality
If you haven’t used your lawn mower in a while, the fuel in the tank may have gone bad. Old gasoline can gum up the carburetor and prevent the engine from starting. The general rule of thumb is to use fuel that is no more than 30 days old. If your fuel is older than that, it’s best to drain it and replace it with fresh fuel.
How to drain the fuel tank:
- Locate the fuel tank drain valve: Most lawn mowers have a small drain valve located at the bottom of the fuel tank.
- Place a container underneath the drain valve.
- Open the valve: The fuel will flow out of the tank into the container.
- Close the valve: Once the fuel has drained, close the valve.
- Dispose of the old fuel properly: Old gasoline should not be poured down the drain. It’s best to take it to a local recycling center or gas station for disposal.
3. Check the Fuel Lines
Fuel lines can become clogged with debris or sediment, preventing fuel from reaching the carburetor. To check the fuel lines,
- Locate the fuel line running from the tank to the carburetor.
- Inspect the line for kinks, cracks, or other damage.
- If the line appears to be in good condition, you can try blowing through it with compressed air. This will help dislodge any debris that may be blocking the flow of fuel.
If the fuel line is clogged, you can try cleaning it with a wire brush or a small piece of pipe cleaner. You can also replace the fuel line with a new one if it is damaged or beyond cleaning.
Battery Issues:
The next most common reason for a lawnmower not starting is a dead or weak battery.
1. Check the Battery Terminals
Corrosion on the battery terminals can prevent a good connection and prevent the battery from delivering power.
- Remove the battery terminals: Disconnect the negative terminal first, then the positive terminal.
- Clean the terminals: Use a wire brush or a battery terminal cleaner to remove any corrosion.
- Reconnect the terminals: Make sure the terminals are clean and securely connected.
2. Check the Battery Voltage
If you suspect the battery is weak, use a voltmeter to check the battery voltage. A fully charged 12-volt battery should have a voltage reading of at least 12.6 volts. If the voltage is below 12 volts, the battery may be too weak to start the mower.
If the battery is weak or dead, you will need to charge it or replace it.
3. Check the Battery Connections
Even if the battery terminals are clean, there may be loose connections in the wiring.
- Inspect the wiring for any loose connections or broken wires.
- Tighten any loose connections and repair or replace any damaged wires.
Ignition Problems:
The ignition system is responsible for creating a spark that ignites the fuel-air mixture in the engine. If there is a problem with the ignition system, the engine will not start.
1. Check the Spark Plugs
Spark plugs are a common point of failure in lawn mowers. Over time, spark plugs can become fouled with carbon deposits or wear out.
- Remove the spark plug: Use a spark plug socket to remove the spark plug.
- Inspect the spark plug: Look for signs of wear, such as a gap that is too wide or a cracked insulator. You should also check for carbon deposits on the electrode.
- Clean or replace the spark plug: If the spark plug is dirty, you can clean it with a wire brush. If the spark plug is worn or damaged, you will need to replace it with a new one.
How to check for a spark:
- Remove the spark plug wire from the spark plug.
- Hold the spark plug wire about 1/4 inch away from a grounded metal surface (like the engine block).
- Have someone crank the engine while you observe the spark plug wire.
- You should see a bright blue spark jumping between the wire and the metal surface.
If you do not see a spark, it indicates a problem with the ignition system.
2. Check the Ignition Coil
The ignition coil is responsible for producing the high voltage that creates the spark.
- Inspect the ignition coil for any signs of damage, such as cracks or burns.
- Test the ignition coil with a multimeter. Most ignition coils have a resistance reading of about 0.5-2 ohms. If the coil is not within this range, it may be faulty.
3. Check the Ignition Wiring
The wiring that connects the ignition components can also become damaged or corroded over time.
- Inspect the wiring for any loose connections, broken wires, or signs of corrosion.
- Repair or replace any damaged wiring.
Carburetor Problems:
The carburetor is responsible for mixing fuel and air in the correct ratio for combustion. A clogged or malfunctioning carburetor can prevent the engine from starting.
1. Clean the Carburetor
- Remove the carburetor from the engine. The location of the carburetor will vary depending on the model of your lawn mower.
- Disassemble the carburetor. Remove the bowl, float, jet, and other parts.
- Clean the parts: Use a carburetor cleaner spray to clean the parts. Be sure to clean all of the jets and passages.
- Reassemble the carburetor: Reassemble the carburetor and install it back on the engine.
Note: If the carburetor is severely clogged, it may need to be rebuilt or replaced.
2. Check the Choke
The choke helps to enrich the fuel-air mixture during starting. If the choke is not working properly, the engine may not start.
- Make sure the choke lever is in the correct position. The choke lever should be pulled out or pushed in, depending on the model of your lawn mower.
- If the choke lever feels stiff or is not working properly, you may need to clean it or lubricate it.
Engine Issues:
If you’ve ruled out all of the above problems, there may be an issue with the engine itself.
1. Check for Engine Flooding
If the engine is flooded, it will not start. This happens when too much fuel is injected into the combustion chamber.
- To remedy a flooded engine, you can try:
- Cranking the engine with the choke off. This will help to clear out the excess fuel.
- Removing the spark plugs and cranking the engine. This will also help to clear out the excess fuel.
- Allow the engine to sit for a few minutes to let the excess fuel evaporate.
2. Check for Low Compression
Low compression can prevent the engine from starting. This is caused by worn or damaged piston rings or valves.
- You can check for low compression using a compression tester.
- If the compression is low, you will need to have the engine repaired or replaced.
3. Check for Mechanical Problems
There may be other mechanical problems with the engine that are preventing it from starting.
- Inspect the engine for any loose or damaged parts.
- If you find any problems, you will need to have the engine repaired.
Additional Tips:
- Check the air filter. A dirty air filter can restrict airflow to the engine and prevent it from starting.
- Check the oil level. Low oil can cause engine damage.
- Make sure the spark plug wire is properly connected.
- If the lawn mower is equipped with a safety switch, make sure it is engaged.
Conclusion:
Troubleshooting a non-starting riding lawn mower can be a frustrating process, but with a systematic approach and a little patience, you can often identify and fix the problem. By starting with the basics like fuel and battery checks and moving on to more complex issues like ignition problems and carburetor troubles, you can hopefully get your lawn mower running smoothly again. Remember, if you’re not comfortable working on the mower yourself, it’s always best to take it to a qualified mechanic.
FAQs
Q1: My riding lawn mower’s engine turns over, but won’t start. What’s wrong?
This is a common issue, often caused by a lack of fuel or a faulty spark plug. First, ensure the fuel tank has enough gas and that the fuel lines are not clogged. A clogged fuel filter can also prevent fuel from reaching the engine. Check the fuel filter and replace it if necessary. If the fuel system is clear, inspect the spark plug. A fouled spark plug will prevent a spark from igniting the fuel, so clean or replace it.
Additionally, ensure the battery is fully charged and has enough power to start the engine. If the battery is weak, jump-starting it might be necessary. You should also check the air filter for obstructions, as a clogged air filter can restrict airflow to the engine and prevent it from starting.
Q2: The engine won’t turn over at all. What’s the problem?
This could indicate a dead battery, a faulty starter, or a problem with the ignition system. First, check the battery terminals for corrosion and ensure they are clean and securely connected. If the battery is weak, jump-starting it might solve the issue. However, if the battery is completely dead, it needs replacement. Next, inspect the starter motor for any damage or loose connections. If the starter motor is faulty, it will need to be replaced. If the starter motor is working but the engine doesn’t turn over, there might be a problem with the ignition switch or the wiring connecting the ignition system to the starter.
Q3: My riding lawn mower starts, but dies quickly. What’s wrong?
This often indicates a fuel-related problem, a faulty spark plug, or a clogged air filter. First, inspect the fuel lines and fuel filter for any blockages. A clogged fuel filter can restrict fuel flow, leading to a quick engine stall. Also, check the fuel tank to ensure there is enough gas and that the fuel line isn’t kinked. Additionally, inspect the spark plug for wear or fouling, as this can cause the engine to die prematurely. If the spark plug is clean, the problem could be a faulty ignition coil or wiring.
Finally, a clogged air filter can restrict airflow and cause the engine to stall. Ensure the air filter is clean and unobstructed. If the problem persists after checking these components, it might be necessary to consult a mechanic for further diagnosis.
Q4: I’ve replaced the spark plug, but my riding lawn mower still won’t start. What’s the next step?
While a faulty spark plug is a common culprit, it’s not the only potential problem. Ensure you’ve installed the new spark plug correctly with the correct gap. Inspect the spark plug wires for any cracks or damage, as this could prevent the spark from reaching the plug. Additionally, check the ignition coil for any signs of damage or corrosion. If the coil is faulty, it will need to be replaced.
Furthermore, verify the ignition system is receiving power. A faulty ignition switch or wiring can also prevent the engine from starting. Check the wiring for any loose connections or damaged wires. If everything seems in order, it might be time to seek professional help.
Q5: My riding lawn mower starts, but runs rough. What could be causing this?
A rough-running engine can indicate various issues, including a faulty spark plug, dirty air filter, clogged fuel filter, or a problem with the carburetor. Start by inspecting the spark plug for wear or fouling. A fouled spark plug can cause the engine to misfire. Clean or replace the spark plug as needed. Additionally, inspect the air filter for dirt or debris, as a dirty air filter can restrict airflow and cause the engine to run rough.
Finally, check the fuel filter for any obstructions, and inspect the carburetor for any signs of dirt or debris. If the carburetor is dirty, it might need to be cleaned or rebuilt.
Q6: My riding lawn mower makes a clicking sound when I try to start it. What does this mean?
A clicking sound when attempting to start the engine usually indicates a problem with the starter motor or the battery. If the clicking sound is consistent and the engine doesn’t turn over, it’s likely a weak or dead battery. Check the battery terminals for corrosion and ensure they are clean and securely connected.
If the battery is fully charged and the clicking sound persists, the problem could be a faulty starter motor. The starter motor engages the flywheel to turn the engine, so if it’s malfunctioning, the engine won’t turn over. A mechanic should inspect and potentially replace the starter motor.
Q7: My riding lawn mower starts but smokes excessively. What is the cause?
Excessive smoke from your riding lawn mower could be caused by several factors, including worn engine parts, problems with the fuel system, or even a malfunctioning air filter. The color of the smoke can give you clues about the underlying issue. Blue smoke usually indicates burning oil, while black smoke points to a rich fuel mixture.
First, check the oil level and ensure it’s within the recommended range. A low oil level can lead to excessive smoke. Next, inspect the fuel system for leaks or obstructions. A clogged fuel filter or a faulty fuel pump can cause a rich fuel mixture, leading to black smoke. Finally, ensure the air filter is clean and unobstructed. A dirty air filter can restrict airflow and cause the engine to run too rich, producing excessive smoke. If the problem persists, it’s recommended to seek professional advice.