Troubleshoot and Repair a Riding Mower That Won’t Start

Again, the grass has to be mowed. This time, however, your lawn mower won’t even start. Use this manual to figure out what’s causing your mower to not start so you can get back to cutting the grass before it gets out of hand.

There are many causes of a riding mower that won’t start, including a dead battery, frayed or corroded cables and wiring, a blown fuse, a broken safety switch, a broken ignition switch, a broken starter solenoid, a broken starter, or engine difficulties.

Avoid getting electrocuted by taking precautions when working with electricity. Be sure to observe all of the security measures mentioned in your mower’s manual.

Before diagnosing, repairing, or operating, be sure you’ve read and understood all of the safety recommendations in the equipment’s operator’s manual.If you don’t feel confident in your ability to make the repair or if you lack the necessary expertise or experience, you should get some help from a professional.

Reasons Your Riding Lawnmower Won’t Start

The Battery Is Dead Or Poor

The battery in your lawn mower is used to kickstart the engine. If the battery is dead or only partially charged, the vehicle’s motor won’t start.

If your mower won’t turn over, check the battery’s charge with a multimeter. You should see around 12.7 volts from a fully charged 12-volt battery.

If the readout is low, try giving the battery a charge. 5 Things That Are Draining the Life of Your Lawn Mower Battery contains instructions on how to conduct a battery test. Find out what can drain your battery and how to fix it here.

To charge a battery, plug it into a battery charger. Put on safety goggles and gloves to guard against electrical burns before proceeding. Here’s how to use a charger for your riding mower’s battery:

  • Get at the terminals and batteries. A screwdriver may be required to access the battery. The battery is either underneath the seat or in the engine compartment. Keep the battery inside its case at all times.
  • Start by plugging in the positive cable to the battery charger. The plus sign cable, or the red cable, is this one.
  • Connect the cable to the battery’s positive pole.
  • Connect the negative end of the cable to the battery’s negative terminal. The negative-sign cable, or black cable, is this.
  • To avoid electrocution, avoid touching anything that isn’t covered in rubber.
  • Change the charger’s voltage and current to suit your needs. Lawn mower batteries typically have a voltage of 12 volts. Higher current speeds up the battery’s charging process. The recommended starting point is 2 amps, with a maximum of 10 amps. It’s best to charge slowly.

A new battery should be used if you notice the old one won’t retain a charge. Batteries for 12v lawn mowers are available at most home improvement and auto shops. Batteries can also be purchased at a store that sells lawnmowers.

Don’t forget to bring the dead batteries. You’ll probably have to pay a core fee if you don’t bring in your old battery. The base cost is often around $20.

Loose Wires and Connections

The riding mower’s jolting and vibration might cause the wiring, plugs, and connectors to fall free. There will be a lack of continuity in the electrical wiring and components.

You should check the connections and wiring for corrosion as well as for loose wires and ensure that they are properly linked. Corrosion brought on by moisture might disrupt operations.

Use a baking soda solution (two cups water to three heaping tablespoons of baking soda) to get rid of the corrosion. Tighten up all of the cables and plugs.

Wires, connectors, and terminals should be replaced if they are rusted or broken.

Fuse Issue

Your riding mower’s electrical components are safeguarded by a fuse. Make sure there is no blown fuse by conducting a thorough inspection.

A blown fuse can be tested by measuring the resistance between the probes of a multimeter placed on the fuse’s prongs. If the resistance is close to zero, your fuse is fine. A blown fuse will show up as a resistance reading of infinite.

A new fuse must be installed if a blown one is discovered. Always use a fuse of the same amperage when replacing an old one. Never switch to a lower amperage.

If the fuse keeps blowing on your riding mower, you should have it checked out by a professional at a lawn mower repair business.

Failure of the Ignition Switch

If inserting and turning the key to start your riding mower does nothing, the problem may lie with the ignition key switch.

whether you suspect the ignition switch is broken, you can test it with a multimeter to see whether there is any continuity. Find the “B” and “S” prongs on the battery and the starter solenoid, respectively.

Put the key in and turn it until you hear the starter sound. Connect one probe to the B prong and the other probe to the S prong of the multimeter when the multimeter is set to the resistance measurement mode.

A good key switch for the ignition will have a resistance reading close to 0 ohms. If the resistance reading on your ignition key switch is infinite, you need to replace it.

Faulty Safety Switch

A riding mower’s safety features, including multiple switches, are all there to protect the user. Mowers are equipped with switches that disable the ignition if certain conditions are not met, such as when the brake is applied.

The failure of a mower to start can be attributed to a faulty safety switch. Apply the multimeter test to the switch. As a troubleshooting measure, you can try briefly disable the safety switch to see whether the problem persists.

Never cut grass without first flipping the mower’s safety switch.Mowers should never be used if the safety switch has been removed. You never know when you might need a safety switch, but having one is always a good idea.

Bad Solenoid for the Starter

When the ignition is turned on, an electromagnetic switch called a starting solenoid sends a signal to the starter motor to crank the engine.

When the copper plate inside the solenoid corrodes or the internal spring weakens, the starting can no longer be relied upon. If the starter is weak, the battery is dead, or the ground is corroded, the solenoid won’t work.

The battery needs to be completely charged before the starter solenoid can be tested. Follow the procedures outlined in “How to Tell Your Lawn Mower Solenoid is Bad” to continue testing the solenoid.

The Starter Motor Is Faulty

The starting should be checked once you have determined that the battery, cables, wiring, ground, and starter solenoid are not at fault for the mower’s inability to start. The starter can be taken out and examined in detail.

Instead of blindly purchasing a new starter, have it tested and maybe rebuilt by a local repair business that specializes in starter and alternator repairs.

Is Your Ride-On Mower Still Giving You Trouble?

When you’ve had a lawnmower for a while, it’s inevitable that various issues may arise. Mower issues can range from smoke or uneven cutting to inability to start or fuel leakage.

Have a look at these helpful charts for answers to often encountered issues with lawn mowers:
Fixing the Most Frequent Issues with Riding Mowers.

If you’re having trouble fixing your mower or would rather have someone else handle it, don’t hesitate to contact a lawn mower repair service in your area.