There’s nothing quite as frustrating as a faulty lawnmower. Fortunately, if your riding lawn mower won’t start and no clicking comes from the engine, you might not need a replacement just yet.

Below, our experts have put together the potential issues with a riding mower that won’t start or click and provide troubleshooting tips to help your riding mower work again.

How to Fix a Riding Lawn Mower That Won't Start

You should be able to find out the problem with your tractor or mower yourself. But first, ensure you set the parking brakes. Then check if the blades are still disengaged. Your riding mower won’t work otherwise.
Stihl lawn mower

Materials You Will Need

  • Work gloves
  • Safety goggles
  • Multi-meter
  • Screwdriver
  • Wire brush

How a Riding Lawn Mower is Powered

Lawn mowers are powered by a four-cycle engine (intake, compression, combustion, and exhaust). Some mowers use gasoline as their fuel and a spark plug to combust it. Others are powered by diesel and require no spark plug. In either case, the engine runs the transmission and drive wheels, and rotates the cutting blades underneath the machine.

Like automobiles, lawn mowers use a battery, starter motor, and ignition switch. When you turn the ignition switch to the ‘Start’ position, 12 volts of direct current travels from the battery through the starter solenoid to the starter motor. This current also flows through a cable to the anti-afterfire solenoid in the engine

Troy-Bilt 382cc 30-Inch Premium Neighborhood Riding Lawn Mower used by a model

When you release the key to the ‘Run’ position, this DC of 12 volts is then redirected. Instead of going to the starter solenoid and motor, it moves to the alternator and anti-afterfire solenoid only. Together, these parts help to charge the battery and run auxiliary power sources like headlights and power plugs.

If your high-quality zero turn mowers work fine, you would hear a clicking sound between the ‘Run’ and ‘Start’ positions. This implies that the starter solenoid is getting power from the battery. On the other hand, when you don’t hear a click from the engine, the starter solenoid has failed, or its coil isn’t getting power from the battery.

Although mowers differ from models, they all work on the same principles.

Check and Charge/Replace Dead Battery

Battery troubles are one of the most common reasons a mower won’t run or click. A corroded battery won’t power an engine, and neither will a drained battery, when you forget to turn off the key.

A service monitor on a mower can help you identify when you’ve got battery troubles. But without one, you can check the battery using a multi-meter by following these steps:

  • Turn off the ignition system before accessing the battery.
  • Set the multi-meter to DC voltage
  • Use the multi-meter's red probe to touch the positive terminal and the black probe on the negative terminal.
If the multi-meter reads more than 12 volts, the battery is good. Otherwise, it is weak, or dead and you’ve found the problem with your mower.
You can recharge relatively new batteries by:
  • Accessing the battery, which is usually under the driver's seat.
  • Connecting the charger clips to the battery terminals.
  • Plugging the charger to a power outlet. The charger should work on at least 10volts to charge the battery. Still, a 12-volt charger is often preferred.
  • Disconnecting the charger reversing the steps above.
  • Plugging the charger to a power outlet. The charger should work on at least 10volts to charge the battery. Still, a 12-volt charger is often preferred.
  • Replacing the seat and reconnecting the battery in your mower correctly.
If a simple recharge doesn’t work, you need to replace the battery pack in the mower. Avoid jumpstarting lawn mowers to prevent damages to the on-board system

Check the Ignition Switch

The problem with your mower could be with the switch. When you start the engine, your ignition switch’s contacts complete a circuit. This circuit is from a red to a white wire, which is on the B-terminal and S-terminal, respectively.
Red riding lawn mower
Our team suggests to check the switch by measuring the resistance between these terminals.
  • Pull up the mower's hood to access the ignition switch.
  • Remove its wire harness.
  • Remove the tabs to pull the ignition switch out of its slot.
  • Turn the key to the start position and set the multi-meter to measure resistance, not voltage.
  • Connect the black multi-meter probe to the B prong and the other to the S prong. These terminals are along each other's diagonal at the bottom of the switch.
  • Use the key to turn the ignition switch and start the engine. The resistance should display on the multi-meter when you do this.

The top-rated riding lawn mowers should have good ignition switch measuring 0 ohms. This means its contacts complete the B and S terminal circuit and can send voltage to the solenoid. On the other hand, a damaged ignition switch will measure infinite resistance.

Other common issues you can experience with a damaged ignition switch include loose wiring and connections, corrosion, or spinning ignition. To fix this problem, check the ignition wiring for corroded, damaged, or loose wires

Inspect the Control Module

A control module is a printed circuit with resistors, relays, and a ground side that receive commands from the key switch. If the sensors in the motor work correctly, a circuit module will also output a command to the starter through the solenoid. However, not every mower has one.
Hurqvarna electric lawn mower cutting deck

Depending on your model, a control module could be anywhere, even under the seat. And if you notice that your high-quality electric riding lawn mower won’t start no clicking comes from the device, or cranking doesn’t work, then this module could be faulty.

There are two ways to check the control module yourself:

  • Wiggle test: Here, wiggle the red and black wires connected to the control module while you start the mower. If everything checks out fine and the wires are connected, visually check the printed circuit for water damage and loose connections. To save time, you could have someone help you with the wires in a wiggle test while you focus on finding the issue.
  • Main fuse check: Modules have internal or external fuses, and a blown fuse cuts out the supply from the battery. First, to check the fuse, remove its zip tie and then pull the fuse from its holder. If any element in the fuse is broken or there's a fault in the ground connection, you should have it replaced. However, if you're unsure, you can check for continuity using your multi-meter.
A good fuse should measure near 0 ohms. On the other hand, a blown fuse will measure infinite resistance.

Check Safety Functions

Every mower even the cheapest riding lawn mower you can find in the market has in-built safety features. Typically, sensors or switches control these features, and they are routed through the control module. Once a detector activates a safety function, your mower won’t work as usual.

The main ones to check are the brake switch, blade switch, weight sensor (to make sure a driver is sitting before the mower works).

When you start the engine, you should press your brake pedal. If the brake pedal doesn’t work, then you need to inspect your brake detector.

  • Remove the hood and air-duct screws.
  • Pull off the air duct and take the fuel tank and filter out of the way.
  • Pull the wire harness off the brake switch, noting the wiring.
  • Using the multi-meter probes, touch both prongs that connect to the wiring of the brake detector.
Lawn mower with shovel, rake, and working boots

If the brake switch is okay, the multi-meter should display 0 ohms of resistance. Replace this switch if you read infinite resistance from your multi-meter.

A riding mower engages when the blade knob is switched off or the transmission isn’t set to park. To check the blade switch, our experts recommend to do the following:

  • Take out the clutch lever mounting screws. The assembly should drop slightly when the screws aren't in place.
  • Note the prong's wiring and then disconnect the blade switch's wire harness.
  • Using your multi-meter probes, touch both prongs to measure the resistance of the blade switch.

Like before, 0 ohms implies your blade switch is good, while infinite resistance means you need to replace it.

Man riding a lawn mower

Motion detectors, switches, and sensors have in-built override functions. These functions are generally used for tests, and simply disconnecting a detector can cause an override. If you suspect your sensors are on an override, our team suggests to reconnect them before starting the device.

Replace Faulty Solenoid

Follow these steps to change a faulty solenoid:
  • First, raise the seat to get to the battery. Then, disconnect the battery terminals, starting with the negative (colored black) and then the red
  • Remove the battery from its slot. While at it, check for leaks or corrosion at the bottom and sides. Clean corrosion off the cable leads with a wire brush if they are still there after dusting.
  • Disconnect the wire harness that's connected to the seat's detector.
  • Pull off the battery box after removing its clips or screws.
  • Note the wiring connected to the solenoid and then disconnect the cables in any order.
  • Remove the mounting and tab both with a screwdriver.
  • Remove the faulty solenoid and replace it with the new one.
  • Finally, replace the seat, battery, and other parts.
While you can repair some solenoids, it’s often better to change them for longevity.

FAQ

Why does my riding lawn tractor click but won't start?

Your riding lawn tractor click but won’t start because the trouble could be from your battery, fuse, control module, or mower’s safety features. You’ll often just need to recharge your battery or change the fuse to power your lawn tractor again.

How do I know if my mower solenoid is bad?

You will know if your mower solenoid is bad when you listen to what happens when you turn the key while starting the mower. You should hear one click when the solenoid engages. If it doesn’t make this sound, your starter solenoid has an issue and needs a repair or replacement.

What do you do when your riding mower won't start?

When your riding mower won’t start, carefully go through the starting procedure. Often, you might have forgotten a step like pressing the parking brake or standing while starting the device. If you’re sure you’ve got everything right and checked the black, red, and white wires, proceed to troubleshoot the problem using the tips above. You’ll save time if you start from a battery and fuse test.

Conclusion

Don’t fret if your riding lawn mower won’t start no clicking comes from the tractor, and cranking doesn’t work. Regardless of your model, our experts’ troubleshooting methods will help you start your mower if you follow these tips to the letter.
Robert