Skip to Content

How to Tell Your Kubota Starter Solenoid is Bad (Step-By-Step)

You attempt to start your mower and the engine won’t turn over. You just hear a humming or clicking sound.

A Kubota starter solenoid is likely bad when the starter motor turns over when the solenoid is bypassed. A starter solenoid that is mounted to the starter can be tested using a battery charger to determine whether it is bad.

Take caution when working with the starter solenoid. Follow all safety precautions listed in your Kubota operator’s manual. When working with the electrical system, remove the black cable first and then the red cable from the battery before making repairs.

This post may include affiliate links. Purchases made through these links may provide a commission for us, at no extra cost to you. As an Amazon Associate, we earn from qualifying purchases.

Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

What Is a Kubota Lawn Mower Solenoid? 

A Kubota lawn mower solenoid is like an on/off switch. It is an electromagnet switch that is actuated to engage the starter motor to turn over the engine.

Where is a Kubota Lawn Mower Starter Solenoid Located?

The Kubota starter solenoid is usually mounted to the starter motor, but it doesn’t need to be to work correctly. Some lawn mower solenoids can be found mounted on the frame closer to the battery than the starter.

Follow the red positive cable from the battery to find the starter solenoid.

Three & Four Post Solenoids 

This is a typical wire schematic of three and four-post solenoids. Remember, not all wire schematics are the same for every lawn mower.

Some schematics will include wiring for options like lights and 12-volt ports on some Kubota mowers. These diagrams only show the basic wiring schematic. 

How to Identify Kubota Lawn Mower Solenoid? 

Solenoids can appear a little differently. Some may be round while others are square. It may have 3 or 4 posts sticking out of it. Some solenoids will be attached at the top of the starter.

The positive (+) wire from the Kubota battery attaches to one side of the solenoid. Following the positive cable from the battery is an easy way to find your solenoid.  

You will find solenoids on every Kubota electric start engine.  

What Causes a Kubota Lawn Mower Starter Solenoid to Go Bad? 

A Kubota solenoid is an electrical switch. Electrical items can fail at any time.

Inside the solenoid, you will find a spring and copper plate. A Kubota starter solenoid can go bad if the spring gets weak or the copper plate starts to corrode.

The solenoid can also fail as a result of a weak starter, bad battery, or bad ground.  

It is good to know what to look for when you are diagnosing a solenoid. 

Symptoms of a Bad Kubota Starter Solenoid on Lawn Mower 

  • Clicking or humming sound when you turn the ignition key and the mower doesn’t start.
  • The wire gets hot and begins to smoke or melt.

Steps to Diagnose a Bad Kubota Lawn Mower Solenoid 

List Tools Needed: 

If you are going to diagnose the solenoid on your lawn mower, there are a few ways to do so. 

1. Make Sure Your Kubota Battery Has a Full Charge

Use your voltmeter to make sure your battery has at least 12.3 volts in it. Read more about testing your battery in our article 5 Reasons Your Kubota Mower Battery Keeps Dying.

2. Get Your Kubota Mower Ready to Start

  • Set the parking brake
  • Make sure your lawn mower is in neutral
  • Turn the key to the on position

3. Bypass the Kubota Starter Solenoid Using a Screwdriver

Lay a long screwdriver over the solenoid to touch the two cables to bypass the starter. The two cables you are looking for are the cable from the battery and the cable to the starter.

It may throw a spark when the screwdriver makes contact with the wires. This is common so don’t be alarmed.

If the engine happens to turn over while you have your solenoid bypassed there is a good chance your solenoid is bad. If the screwdriver does not work well, you can also use needle nose pliers to jump the solenoid. 

Before you replace the starter solenoid, check for loose or corroded wires or bad ground. These items can keep the solenoid from getting the power it requires to work. 

4. Test the Kubota Starter Solenoid

Solenoids that are mounted on the starter can be tested. Remove the starter from the engine and test the solenoid with a battery charger. This is a good way to watch if the starter is working with the solenoid. 
 
Once the starter has been removed from your lawn mower, you need to attach the negative (-) clamp to the case of the starter and touch the positive (+) clamp to the big post and exciter wire on the solenoid. This is just a quick bench test when the starter is out. 

Can You Bypass a Kubota Lawn Mower Starter Solenoid? 

A Kubota starter solenoid can be bypassed by placing a long screwdriver across the solenoid from touching the cable from the battery to the cable to the starter.

Be careful. The connection could cause a spark which is normal. Always wear safety gear.

Another reason why your mower may not start is due to water in the electrical system. Check out Why Your Mower Won’t Start After Leaving in the Rain for more information. 

Still Experiencing Problems with your Kubota Lawn Mower?

Own a lawn mower long enough, you’ll start running into problems with it starting, not continuing to run, smoking, leaking gas, giving a bad cut, vibrating, or another issue.

To help you save time and money, I have put together a guide to help you troubleshoot the next problem that develops on your Kubota mower.

You can find this guide at Common Kubota Lawn Mower Problems & Solutions.

If you are unsure how to perform diagnostics and repairs on your Kubota lawn mower safely, it’s best to have a professional complete the repairs.

This will help you avoid personal injury or additional damage to the mower. Your local Kubota lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.