Hearing that dreaded “click, click, click” when you turn the key on your lawnmower is frustrating, especially when you’re ready to tackle your yard work. It’s a common problem that many homeowners face, and while it can seem daunting, understanding the potential causes can help you diagnose and fix the issue yourself. This comprehensive guide will walk you through the most likely reasons your mower is clicking but not starting, and provide practical solutions to get your machine back in action.
Understanding the Clicking Sound
That clicking sound you hear is usually the sound of the starter solenoid attempting to engage the starter motor. The solenoid acts like a switch, receiving a small electrical current from the ignition switch and using it to activate the larger current needed to power the starter motor. When the solenoid clicks, it indicates that it’s receiving power and trying to do its job. The problem is that something is preventing the starter motor from actually turning the engine over. It’s like a relay switch that is trying to flip, but unable to complete the circuit effectively.
Common Culprits: Electrical Issues
Electrical problems are the most frequent cause of a mower clicking but not starting. Let’s delve into the specific electrical components that might be at fault.
The Battery: Low Voltage or Dead
The battery is the heart of your mower’s electrical system. A weak or dead battery simply can’t provide enough power to the starter motor to turn the engine.
- Check the Battery Voltage: Use a multimeter to test the battery voltage. A fully charged 12-volt battery should read around 12.6 volts. If it’s significantly lower (below 12 volts), the battery is likely the problem.
- Jump Starting: Try jump-starting the mower with a car battery (being extremely careful to connect the cables correctly – positive to positive, negative to a grounded metal part of the mower). If the mower starts with a jump, the battery is definitely weak or dead.
- Battery Terminals: Examine the battery terminals for corrosion. Corrosion can impede the flow of electricity. Clean the terminals with a wire brush or a terminal cleaning tool. Apply a thin layer of dielectric grease to prevent future corrosion.
- Battery Age: Batteries have a limited lifespan, typically 3-5 years. If your battery is old, it may be time for a replacement.
Loose or Corroded Connections
Electricity needs a clear path to flow. Loose or corroded connections can create resistance, preventing sufficient power from reaching the starter motor.
- Inspect All Connections: Carefully inspect all electrical connections, especially those related to the battery, solenoid, starter motor, and ignition switch.
- Clean Connections: Disconnect each connection, clean it with a wire brush or sandpaper, and reattach it securely. Apply dielectric grease to protect against corrosion.
- Check Ground Connections: Pay particular attention to the ground connections. A poor ground connection is a common cause of electrical problems. Ensure the ground wire is securely attached to a clean, unpainted metal surface on the mower frame.
Faulty Starter Solenoid
As mentioned earlier, the solenoid is responsible for relaying power to the starter motor. If the solenoid is faulty, it may click but fail to deliver the necessary current.
- Test the Solenoid: You can test the solenoid using a multimeter. Check for voltage at the solenoid when the ignition switch is turned to the start position. If there’s voltage going in but not coming out, the solenoid is likely bad.
- Solenoid Replacement: Replacing a solenoid is usually a straightforward process. Disconnect the battery, remove the wires from the old solenoid, and attach them to the new solenoid in the same configuration.
Damaged Wiring
Damaged or frayed wires can interrupt the flow of electricity.
- Visual Inspection: Carefully inspect all wiring for signs of damage, such as cuts, breaks, or frayed insulation.
- Continuity Test: Use a multimeter to perform a continuity test on the wires. If there’s no continuity, the wire is broken and needs to be replaced.
Faulty Ignition Switch
The ignition switch sends the signal to start the engine. If the switch is faulty, it may not be sending the signal properly.
- Test the Switch: Testing an ignition switch can be a bit more complex and might require a wiring diagram for your specific mower model. You can use a multimeter to check for continuity in different switch positions.
Mechanical Issues Preventing Starting
While electrical issues are more common, mechanical problems can also prevent the starter motor from turning the engine over.
Seized Engine
A seized engine is the most severe mechanical issue. This means the internal components of the engine are locked up, preventing it from turning.
- Causes of Seizure: Lack of lubrication (low oil), overheating, or internal damage can cause an engine to seize.
- Attempt to Turn the Flywheel: Try to manually turn the engine flywheel. If it won’t budge, the engine is likely seized.
- Professional Help: A seized engine often requires professional repair or engine replacement.
Starter Motor Problems
The starter motor itself could be the problem. It might be internally damaged or have worn-out brushes.
- Direct Power Test: Carefully (being mindful of potential sparks and short circuits), try directly connecting the starter motor to the battery using jumper cables. If the starter motor spins, the problem is likely not the starter itself, but rather the solenoid or the wiring leading to it. If it doesn’t spin, the starter is likely faulty.
- Starter Motor Replacement: Replacing the starter motor is a common repair. Disconnect the battery, remove the bolts holding the starter in place, disconnect the wiring, and install the new starter in the reverse order.
Blade Obstruction
Sometimes, debris can get lodged under the mower deck, preventing the blades from turning freely. This can put excessive strain on the starter motor.
- Inspect Under the Deck: Carefully inspect the underside of the mower deck for any obstructions, such as grass clippings, twigs, or rocks.
- Remove Obstructions: Remove any obstructions you find.
Flywheel Brake Engaged
The flywheel brake is designed to stop the engine quickly when you release the handle. If the brake is stuck or misadjusted, it can prevent the engine from starting.
- Check Brake Cable and Lever: Examine the brake cable and lever to ensure they are moving freely and that the brake is disengaged when the handle is released.
- Adjust Brake: If the brake is misadjusted, you may need to adjust the cable tension or the position of the brake lever. Consult your mower’s owner’s manual for specific instructions.
Fuel System Issues: A Contributing Factor
While not directly causing the “clicking” sound, fuel system problems can prevent the engine from starting even if the starter motor is working correctly. Addressing fuel issues can sometimes resolve a seemingly electrical problem.
Old or Stale Fuel
Old gasoline can break down and become gummy, clogging the carburetor and preventing the engine from starting.
- Drain the Fuel Tank: Drain the old fuel from the tank and replace it with fresh gasoline.
- Fuel Stabilizer: Add a fuel stabilizer to the gasoline to prevent it from deteriorating.
Clogged Carburetor
A clogged carburetor is a common cause of starting problems, especially in mowers that have been stored for a long period.
- Carburetor Cleaning: Cleaning the carburetor involves disassembling it, cleaning the jets and passages with carburetor cleaner, and reassembling it. This can be a complex task, so if you’re not comfortable doing it yourself, it’s best to take it to a professional.
- Carburetor Replacement: In some cases, it may be easier to simply replace the carburetor.
Fuel Filter Issues
A clogged fuel filter restricts the flow of fuel to the engine.
- Fuel Filter Inspection: Inspect the fuel filter and replace it if it’s clogged or dirty.
Safety Interlock Switches: Don’t Overlook Them
Most lawnmowers have safety interlock switches that prevent the engine from starting unless certain conditions are met, such as the blade engagement lever being disengaged or the operator being seated.
- Check Interlock Switches: Inspect all safety interlock switches to ensure they are functioning correctly. Common locations for these switches include the blade engagement lever, the operator seat (on riding mowers), and the parking brake.
- Test Switches: You can test the switches using a multimeter to check for continuity.
Step-by-Step Troubleshooting Guide
Here’s a structured approach to diagnosing why your mower is clicking but not starting:
- Check the Battery: Test the battery voltage and clean the terminals. Try jump-starting the mower.
- Inspect Connections: Examine all electrical connections for looseness or corrosion. Clean and secure them.
- Test the Solenoid: Check for voltage at the solenoid when the ignition switch is turned to the start position.
- Inspect Wiring: Look for damaged or frayed wires.
- Check Safety Interlock Switches: Ensure all safety interlock switches are functioning correctly.
- Inspect for Obstructions: Check under the mower deck for any obstructions preventing the blades from turning.
- Check Fuel: Drain the fuel tank and replace it with fresh gasoline.
- Consider Mechanical Issues: If none of the above steps work, suspect a mechanical problem such as a seized engine or a faulty starter motor.
Prevention is Key
Preventing starting problems is much easier than fixing them. Here are some tips to keep your mower in good working order:
- Regular Maintenance: Follow the manufacturer’s recommended maintenance schedule, including changing the oil, cleaning the air filter, and replacing the spark plug.
- Proper Storage: Before storing your mower for the winter, drain the fuel tank or add fuel stabilizer to prevent the fuel from deteriorating. Disconnect the battery and store it in a cool, dry place.
- Use Fresh Fuel: Always use fresh gasoline and avoid using fuel that has been sitting for more than a few months.
- Clean the Mower: Regularly clean the mower deck to prevent grass clippings from building up and causing problems.
When to Call a Professional
While many starting problems can be resolved with basic troubleshooting and maintenance, some issues require professional expertise. If you’re not comfortable working on your mower or if you’ve tried all the troubleshooting steps and the mower still won’t start, it’s best to take it to a qualified mechanic. They have the tools and knowledge to diagnose and repair more complex problems. Knowing when to concede and seek professional assistance can save you time, money, and potential frustration. Don’t hesitate to consult an expert if you’re unsure about any repair.
Solving a “clicking but won’t start” issue on your lawnmower involves a systematic approach. By following the troubleshooting steps outlined in this guide and understanding the potential causes, you can often diagnose and fix the problem yourself. Remember to prioritize safety when working on your mower, and don’t hesitate to seek professional help if needed. With a little patience and effort, you can get your mower running smoothly and keep your lawn looking its best.
Why does my lawn mower only click when I try to start it?
The clicking sound you hear is usually the sound of the starter solenoid trying to engage the starter motor. This often means there isn’t enough power reaching the starter motor to turn the engine over. Several factors can cause this, but the most common are a weak battery, corroded battery connections, or a faulty solenoid itself. It could also be a problem within the starter motor, preventing it from functioning even with sufficient power.
To diagnose the problem, start by checking the battery voltage with a multimeter. A fully charged battery should read around 12.6 volts. Clean any corrosion from the battery terminals and cable connections. If the battery is good and the connections are clean, the solenoid or starter motor itself may be faulty and require testing or replacement. A professional mechanic may be needed for these more complex tests.
How can I test the battery on my lawn mower?
Testing your lawn mower battery is crucial for diagnosing starting problems. The easiest way is to use a multimeter set to DC volts. Connect the red probe to the positive terminal of the battery and the black probe to the negative terminal. Observe the voltage reading on the multimeter. A fully charged 12-volt battery should read approximately 12.6 volts or higher.
If the reading is significantly lower than 12.6 volts, the battery is likely discharged or damaged. You can try charging the battery using a battery charger specifically designed for lawn mower batteries. After charging, retest the voltage. If the voltage still remains low or drops quickly after charging, the battery may need to be replaced.
What is a starter solenoid and how does it work in a lawn mower?
The starter solenoid is an electromagnetic switch that relays power from the battery to the starter motor. When you turn the key or pull the starting cord, a small amount of electricity flows to the solenoid’s coil. This creates an electromagnetic field that pulls a plunger, bridging the high-current circuit between the battery and the starter motor.
Essentially, the solenoid acts as a gatekeeper, allowing a large surge of power to flow to the starter motor only when needed to crank the engine. If the solenoid is faulty, it may not be able to make a solid connection, resulting in a clicking sound as it tries to engage without successfully delivering the necessary power to the starter motor. A bad solenoid can be the reason for a clicking noise without the mower starting.
How do I clean corroded battery terminals on my lawn mower?
Corrosion on battery terminals can significantly impede the flow of electricity, causing starting problems. To clean corroded terminals, first disconnect the negative cable and then the positive cable from the battery. Prepare a solution of baking soda and water (approximately one tablespoon of baking soda per cup of water).
Using a stiff brush (an old toothbrush works well) or a battery terminal cleaning tool, scrub the terminals and cable connectors with the baking soda solution. Rinse thoroughly with clean water and dry the terminals completely. Apply a thin coating of petroleum jelly or battery terminal protector to the terminals to prevent future corrosion. Reconnect the cables, ensuring they are tight and secure, starting with the positive cable and then the negative cable.
Can a loose or damaged wire cause my mower to click but not start?
Yes, loose or damaged wires are a common culprit behind a clicking sound but no start. The wires carry the electrical current necessary to activate the starter solenoid and subsequently the starter motor. If a wire is loose, corroded, or damaged, it can create a break in the circuit, preventing sufficient power from reaching these components. This often results in the starter solenoid clicking without engaging the starter motor.
Inspect all wiring connections related to the starting system, paying close attention to the battery cables, solenoid wires, and starter motor wires. Look for signs of corrosion, fraying, or loose connections. Tighten any loose connections and replace any damaged wires. If corrosion is present, clean the affected areas as described earlier for battery terminals. This thorough inspection and repair process can often resolve the clicking-but-not-starting issue.
What role does the spark plug play in starting my lawn mower and could it cause a clicking sound?
The spark plug is responsible for igniting the air-fuel mixture in the engine cylinder, initiating the combustion process that powers the lawn mower. While a faulty spark plug typically prevents the engine from running smoothly *after* it starts, it usually doesn’t directly cause a clicking sound when attempting to start the mower. The clicking noise is almost always related to the electrical system, specifically the starter and its components.
However, a severely fouled or incorrect spark plug can make the engine harder to turn over, potentially putting extra strain on the starter motor and battery. This increased strain *could* indirectly contribute to a weaker electrical signal reaching the starter, making a pre-existing issue (like a weak battery) more noticeable and leading to the clicking sound. It’s always good practice to check the spark plug, but it’s unlikely the direct cause of the clicking.
What if I’ve checked the battery, connections, and solenoid, and it’s still clicking?
If you’ve ruled out the common causes of a clicking-but-not-starting lawn mower, such as a weak battery, corroded connections, and a faulty solenoid, the problem likely lies within the starter motor itself. The starter motor could have worn brushes, damaged windings, or a faulty internal mechanism that prevents it from turning the engine over. It’s also possible the engine is seized, putting too much load on the starter.
At this point, further diagnosis and repair may require specialized tools and expertise. Testing the starter motor directly with a multimeter can help determine if it’s receiving power and functioning correctly. If the starter motor is confirmed to be faulty, it will need to be replaced. If the engine is seized, professional repair or engine replacement will be necessary.