Your mower isn’t much good when you can’t get the blades to spin because of worn or failing parts.
Ferris zero-turn mower blades won’t engage or turn on due to a worn deck belt, worn idler tensioner arm, worn tensioner spring, bad pulley, faulty PTO switch, bad clutch, weak battery, bad safety switch, or a blown fuse.
Follow all safety precautions found in your Ferris operator’s manual including removing the ignition key and spark plug wires. Wait for all parts to stop moving.
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Follow all safety instructions provided in your equipment operator’s manual before 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.
Ferris Mower Blades Won’t Turn On or Engage
Faulty PTO Switch
The PTO switch is a knob installed on the mower that allows voltage from the battery to power the clutch. When the switch fails, the blades won’t turn on.
Check for continuity in the switch. Replace a switch with a break in continuity.
The Ferris PTO (Power Take Off) clutch transfers power from the engine to the blades by engaging the drive belt. A clutch that is worn or faulty must be replaced when it fails to power the blades.
For more details on clutches, check out A Look into How Lawn Mower Clutches Work.
An electric clutch requires power from the battery. A weak battery may not be able to provide the power required for the clutch solenoid so the mower blades are engaged.
Check for a weak battery using a multimeter. A fully charged 12-volt battery should give you a reading of about 12.7 volts.
Charge the battery when you get a reading less than this. If your battery continues to die you can find common things that are causing this in 5 Things That Are Draining the Life of Your Lawn Mower Battery.
Charge a Ferris Battery: Use a battery charger to charge a battery. Before you continue, wear protective gear to protect your skin from electrical shock and protect your eyes. Follow these steps to charge your riding mower or zero-turn battery with a charger:
- Access the battery and terminals. You may need to use a screwdriver to uncover the battery. You will find the battery under the hood or under the seat. Do not remove the battery from the casing.
- Connect the battery charger 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 you find the Ferris battery won’t hold a charge, you must replace it with a new battery.
You can find 12-volt lawn mower batteries at your local hardware or automotive store. You will also find batteries at your local lawn mower dealership. Purchase a battery with at least 300 CCA (cold cranking amps) to power an electric clutch.
Bring the old battery with you. Most places will charge you a core fee unless you provide them with your old battery. Core fees are typically between $15 and $25.
Bad Safety Switch
A Ferris zero-turn uses several safety switches as part of its operator presence system to help keep the user safe. One of those switches is the seat switch installed under the seat.
The safety system is designed to stop the blades when the operator isn’t in the seat. A seat switch that isn’t working correctly can prevent the blades from turning.
Test the seat switch using a multimeter or you can temporarily bypass the safety switch to identify a bad switch. Do not operate a mower without the safety switch installed for your safety.
Always have safety switches installed and working on your equipment.
A fuse can blow when it is protecting the electrical system from a surge in power or a short. This can cause the clutch to not receive power from the battery.
Replace a blown fuse with the same capacity fuse. If you continue to blow the fuse, I recommend taking your mower to a Ferris service dealership or a repair shop to identify the root cause of the problem.
Worn Deck Belt
A worn deck belt will not sufficiently grip the pulleys to turn the blades. It may slip on the pulleys.
Inspect the belt and look for signs of wearing including cracks, stretching, fraying, or a glazed appearance. A thinner belt that sits deep in the pulley grooves is also a sign of a worn belt.
Replace a worn Ferris belt. Even if the belt isn’t the main reason why your blades won’t engage, you must replace it when it begins to show signs of wearing.
The belt gripping the pulleys affects blade speed. A fast blade speed is required to create suction under the deck to lift the grass and give it a nice even cut.
Worn Idler Tensioner Bracket & Spring
The tensioner bracket and spring hold the idler pulleys in line. You will typically find a pulley on one side of the bracket and a spring on the other side.
The hole in the bracket where the spring attaches can become worn or the spring itself can become worn or broken. This can cause the belt to become loose and fall off the pulleys so the blades no longer turn.
A Ferris belt that keeps coming off your mower deck pulleys can be the result of bad bearings in the pulleys. Bearing failure can cause a pulley to wobble so it no longer sits flat and parallel to the deck.
One side of the pulley should not be sitting higher off the deck than the other. The belt can roll off a pulley that isn’t running flat. Replace a pulley where the bearing is found to be bad.
Read Ferris Zero Turn Belt Keeps Coming Off for additional items that can cause the belt to fall off and no longer turn the blades.
Still Having Problems with Your Ferris Lawn Mower?
No matter what type of mower you own, you will run into problems during its life.
Because of this, I have compiled a list of common Ferris lawn mower problems and solutions to help you troubleshoot the next time your mower doesn’t start, keeps dying, has a bad cut, is overheating, or has another issue.
This is an excellent guide to bookmark so you can refer to it when you need help finding and fixing your mower. You can find this guide at Common Ferris Zero Turn Mower Problems and Solutions.