Is Your Riding Lawn Mower’s Solenoid the Culprit?

The whirring of your riding lawn mower engine, the satisfying clip-clop of the blades cutting through the grass – these are the sounds of summer bliss. But what happens when that beautiful symphony turns into a sputtering, hesitant silence? A malfunctioning solenoid could be the culprit, leaving you staring at your mower with frustration. This article will guide you through the process of diagnosing and checking your solenoid, helping you pinpoint the problem and get your mower back in action.

Essentially, the solenoid acts as a powerful switch that controls the flow of electricity from the battery to the starter motor. When you turn the key, the solenoid receives a signal and activates, creating a connection that allows the starter motor to spin and turn the engine over. If the solenoid fails, the starter motor won’t receive power, and your lawn mower won’t start.

Identifying the Solenoid: Where Is It Hiding?

The first step is to locate your lawn mower’s solenoid. It’s usually a cylindrical metal component with a couple of large terminals, situated near the starter motor. You’ll likely find it attached to the starter itself, the battery, or even the frame of the mower.

Tips for Finding the Solenoid:

  • Consult your owner’s manual: This is your ultimate guide to your mower’s specific components.
  • Look for a large, heavy-duty wire: The solenoid receives power from the battery via a thick, robust wire.
  • Follow the wiring: Trace the path of the large wire leading from the battery to the starter, as the solenoid will be situated along this path.

Checking the Solenoid: A Hands-on Approach

Once you’ve located the solenoid, you’re ready to perform some tests. Here’s how to check its functionality:

1. Visual Inspection: A Quick Look for Obvious Issues

  • Check for loose connections: Ensure the wires connected to the solenoid are secure and not corroded.
  • Inspect for physical damage: Look for signs of wear, cracks, or any visual damage to the solenoid’s casing.
  • Check the solenoid’s condition: If the solenoid looks significantly damaged or corroded, it’s a good indication it needs replacement.

2. The Jumper Cable Test: Testing for Power Flow

This simple test will help you determine if the solenoid is receiving power and activating correctly.

  • Gather your materials: You’ll need a pair of jumper cables and a reliable source of power, like another vehicle’s battery.
  • Connect the jumper cables: Connect one end of the jumper cable to the positive (+) terminal of your mower’s battery. Attach the other end of the jumper cable to the positive (+) terminal of the auxiliary battery.
  • Connect the other jumper cable: Connect one end of the remaining jumper cable to the negative (-) terminal of the auxiliary battery.
  • Touch the other end of the jumper cable to the solenoid terminal: This terminal will be the one that connects to the starter motor. If the solenoid is working, you should hear a clicking sound as it activates.

3. The Battery Test: Ruling Out Battery Problems

A weak battery can also cause starting issues, mimicking a failing solenoid. A quick battery test will help you eliminate this possibility.

  • Use a voltmeter or multimeter: These tools are readily available at most auto parts stores.
  • Connect the voltmeter: Connect the positive (+) lead of the voltmeter to the positive (+) terminal of the battery and the negative (-) lead to the negative (-) terminal of the battery.
  • Check the battery voltage: A fully charged battery should read around 12.6 volts. A reading below 12 volts indicates a weak battery that may need charging or replacement.

Troubleshooting and Replacement: What to Do Next

If your solenoid fails the jumper cable test or you notice significant damage during the visual inspection, it’s time for a replacement.

1. Finding the Right Solenoid: Matching the Specs

  • Check your owner’s manual: It will provide the specific solenoid model number for your mower.
  • Check the solenoid’s specifications: Look for the voltage rating, current rating, and mounting type. Ensure the replacement solenoid matches these specifications.
  • Locate a reputable retailer: Auto parts stores, online retailers, and your mower’s manufacturer are good sources for replacement solenoids.

2. Replacing the Solenoid: A Simple Procedure

  • Disconnect the battery: This is essential for safety and prevents accidental sparking.
  • Remove the old solenoid: Loosen the mounting bolts and disconnect the wires from the old solenoid.
  • Install the new solenoid: Secure the new solenoid in the same position as the old one, ensuring the mounting bolts are tight.
  • Reconnect the wires: Connect the wires to the new solenoid, ensuring they are secure.
  • Reconnect the battery: Once everything is connected, you can reconnect the battery.

Additional Tips for Smooth Sailing

  • Keep the battery terminals clean: Corrosion on the terminals can impede power flow and lead to starting problems.
  • Test the starter motor: A failing starter motor can also prevent your mower from starting. If the solenoid is working but the mower still won’t start, test the starter motor.
  • Check the engine’s fuel supply: Ensure the fuel tank is full, the fuel lines are clear, and the fuel filter is not clogged.

The Solenoid’s Role in a Healthy Lawn Mower

A functioning solenoid is crucial for a smooth-running lawn mower. By understanding how to check and replace it, you can prevent frustrating downtime and ensure a successful mowing season. Remember to always prioritize safety, consult your owner’s manual for specific instructions, and consider seeking professional assistance if you’re unsure about any aspect of the process. With a little knowledge and a few simple steps, you can keep your lawn mower running strong and your yard looking pristine.


What is a solenoid and what does it do in a riding lawn mower?

A solenoid is an electromagnetic switch that is used to start the engine in a riding lawn mower. It’s essentially a coil of wire wrapped around a movable iron core. When you turn the key, electricity flows through the coil, creating a magnetic field that pulls the iron core, which in turn engages the starter motor. It acts as a bridge between the battery’s power and the starter motor, only allowing electricity to flow when the ignition key is turned.

How can I tell if the solenoid is bad in my riding lawn mower?

There are a few signs that could indicate a faulty solenoid. If your riding lawn mower makes a clicking sound when you turn the key but doesn’t start, this could be a sign that the solenoid isn’t engaging properly. Another sign is if you can hear a clicking sound coming from the solenoid itself. Additionally, if you can smell a burning odor coming from the solenoid, this is a clear indication that it’s faulty and needs to be replaced.

How do I test the solenoid?

To test the solenoid, you’ll need a multimeter. Start by disconnecting the battery cables to prevent any potential electrical shocks. Then, use the multimeter to check the continuity of the solenoid’s contacts. If there’s no continuity, the solenoid is bad and needs to be replaced.

How do I replace the solenoid?

Replacing the solenoid is a relatively simple process. You’ll need to locate the solenoid, which is usually mounted near the starter motor. Disconnect the wiring harness and the battery cables. Then, remove the bolts that hold the solenoid in place. Install the new solenoid, making sure to connect the wiring harness and battery cables securely. Finally, tighten the bolts to secure the solenoid in place.

How much does a new solenoid cost?

The cost of a new solenoid for a riding lawn mower varies depending on the make and model of your mower. However, they are generally inexpensive, ranging from around $20 to $50. You can purchase a replacement solenoid from most lawn and garden equipment retailers or online retailers.

Is it safe to replace a solenoid myself?

Replacing a solenoid is generally considered a safe task, but it’s important to follow proper safety precautions. Always disconnect the battery cables before working on any electrical components to avoid the risk of electric shock. Also, make sure to wear safety glasses to protect your eyes from any potential debris.

What are some other reasons my riding lawn mower might not start?

While a bad solenoid is a common culprit, there are several other reasons why your riding lawn mower might not start. The battery could be dead, the spark plugs could be fouled, or the fuel system could be clogged. You should check all of these components before replacing the solenoid.

Leave a Comment