When you go to start your zero-turn, you may hear a clicking sound or a hum, and the engine won’t turn over. This is often due to the starter motor not getting the power it requires to spin the engine.
A SCAG zero-turn won’t turn over or crank when the battery is weak, the wiring and components are loose or corroded, the fuse is blown, the ignition switch is bad, the safety switch is faulty, the starter solenoid is bad, or the starter motor is bad.
Always remove the black negative battery cable prior to making repairs to the electrical system. Take all safety precautions to prevent injuries when working with the electrical system.
Why Your SCAG Zero Turn Mower Won’t Turn Over
Dead or Bad Battery in Your SCAG Zero Turn
A dead battery won’t provide the power you need to turn over your SCAG zero-turn. Keep your battery charged, especially during storage, to extend your battery’s life.
Test your battery using the steps in the article 5 Things That Are Draining the Life of Your Lawn Mower Battery.
Charging a Battery: Use a battery charger to charge your 12-volt battery. Before you continue, wear protective gear to protect your eyes and skin from electrical shock. Follow these steps to charge your lawn mower battery with a charger:
- Access the battery and terminals. You may need to use a screwdriver to uncover the battery. Do not remove the battery from the casing.
- Connect the charging cables beginning with the positive cable first. This is the red cable or the one with the plus sign. Place the cable on the positive battery terminal.
- Attach the negative cable to the negative battery terminal. This is the black cable or the one with the negative sign.
- Do not touch anything that doesn’t have a rubber coating to prevent electrocution.
- Set the charger’s voltage and amperage level to the desired level. The average volt level for lawn mower batteries is usually 12 volts. More amperage charges the battery faster. Start with two amps and work up to no more than 10 amps. A slow charge is best.
If the battery fails to hold a charge it must be replaced with a new battery. You can purchase a new battery at your location lawn mower dealership, hardware store, or automotive store.
Bring your old battery with you. Most places will charge you a core fee unless you provide them with your old battery.
Loose or Wires and Connections in Your SCAG Zero Turn
The wiring and electrical components can shake loose from the vibration of the SCAG mower. Inspect these items and ensure they are securely attached making good connections.
Look for corrosion buildup due to moisture on the components. Corrosion can affect continuity and needs to be removed.
To clean the components, first, remove the battery cables. Next, remove the corrosion using a wire brush and a baking soda solution (2 cups water to 3 heaping tablespoons of baking soda).
Replace the terminals or other components if you aren’t able to get them clean.
Bad Fuse on Your SCAG Zero Turn
A fuse is installed to protect your SCAG electrical system. Check your mower to make sure you don’t have a blown fuse. If you’re unsure if the fuse is blown, you can check it by placing a multimeter probe on each prong of the fuse to measure resistance.
A resistance reading near 0 means your fuse is good. An infinity resistance reading indicates a bad fuse.
Replace a blown fuse with the same amperage as the fuse you are replacing. If you continue to blow fuses, you should bring your SCAG to your lawn mower dealership or lawn mower repair shop to troubleshoot the root cause.
Bad Ignition Switch on Your SCAG Zero Turn
The ignition key switch can be the culprit if you insert the key and turn it to find nothing happens. Your SCAG will fail to turn over and start.
Check the switch using a multimeter to check continuity to determine if the ignition switch is the problem. To do this, look for the prongs mark B for Battery and S for Starter Solenoid.
Insert the key and turn it to the start position. With the multimeter set to measure resistance, touch one probe to the B prong and the other probe to the S prong.
A good ignition key switch will measure resistance near 0 ohms. A bad ignition key switch will measure infinite resistance and will need to be replaced.
Bad Safety Switch on Your SCAG Zero Turn
Your SCAG has an operator presence control system installed to keep you safe. A safety switch can be defective and cause your SCAG to fail to turn over.
Test your switch using a multimeter. You can also temporarily bypass the safety switch to identify a bad switch, but only do this for troubleshooting purposes.
Never operate a mower without the safety switch. Never run a mower when a safety switch is bypassed. A safety switch can save you from serious injury and you never know when you’re going to need it.
Bad Starter Solenoid in Your SCAG Zero Turn
A starter solenoid is an electromagnetic switch that, when engaged, initiates the starter motor to turn over your SCAG engine.
The starter solenoid can go bad when the spring becomes weak or the copper plate begins to corrode. A weak starter, bad battery, or bad ground can also cause the solenoid to fail.
Before you test your starter solenoid, you must have a fully charged battery. Continue testing the solenoid by using the steps to diagnose a bad starter solenoid in How to Tell Your Lawn Mower Solenoid is Bad.
Bad Starter Motor on Your SCAG Zero Turn
Once you have ruled out the battery, cables, wiring, ground, and starter solenoid as being the reason your SCAG won’t turn over, it’s time to look at the starter. The starter can be removed and tested.
I recommend having your local repair shop that specializes in starter and alternator repairs test your starter and rebuild it if possible before just throwing a pricey new starter at your SCAG mower.
Still Experiencing Problems with Your SCAG 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 mower.
You can find this guide at Common SCAG Lawn Mower Problems & Solutions.
If you are unsure how to perform diagnostics and repairs on your 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 SCAG lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.