Today’s hot topic — mower PTO, short for power take-off. The PTO is an important component of a pulley system that powers the blades of your riding lawnmower.
It operates off the electric clutch system in your engine, but just like any other part of your mower can fail by itself or cause other parts of the mower to malfunction such as the fuse.
If your mower is blowing fuse when the PTO is engaged, there’s no reason to break a sweat just yet, because I’ve listed the reasons and fixes for the problem.
Mower Blows Fuse When PTO Engaged? [6 Reasons & Fixes]
1. Short in a Switch or Wires
After a period of use, it’s normal for a switch or wires to experience a short circuit so when you engage the PTO, it blows the fuse.
Pro Tip:If you smell a burning smell coming from the PTO clutch system, then great chances are that you have a short circuit.
The electrical short in this case has something to do with the PTO safety switch, wire, or circuit.
You can open the PTO system of your mower to determine where the short is but I highly recommend contacting your local dealer as fixing a short circuit isn’t a straightforward task but can be risky.
2. PTO Wire Harness is Located Near the Drive Pulley
The wire harness of the PTO in certain mower models is located close to the drive pulley of the machine.
The harness after a certain time tends to drop and comes in contact with the pulley, which grinds through the coating and causes a short circuit.
Pro Tip:Check the harness for any damage, which indicates it has been in contact with the pulley.
If you notice this type of damage, tape up the wiring and relocate the wire to the other side of the crank pulley. You can do this with zip ties or tape.
3. Relay Switches Burnt Out
There are reverse lockout switches located under the side panels on each side of the mower. These switches are designed to stop the blades when both handles are pulled back.
There are usually two switches, and if either one or both of them is out, the deck will fail to engage. Adding to this, when you sit on the seat, there are three relay switches under the right side panel.
The closest relay switch to the motor controls the PTO.
Pro Tip:If this switch is damaged, the PTO will not engage and will blow a fuse.
Check to see if there are any signs of damage. If so, replace the switch and then the fuse.
4. Clutch May be Damaged
If the PTO clutch is damaged, it can cause the fuse to blow. A damaged clutch will affect the movement of the mower.
Pro Tip:To identify if the clutch is causing the PTO and fuse burnout problem, ride the mower in both front and reverse directions to feel for sluggish operation.
You can probably fix the clutch yourself by first parking the mower on a flat surface, turning off the mower, and waiting for it to completely cool down.
Next, locate the spark plug on the side of the engine assembly under the hood and disconnect the ignition wire from the back of the spark plug.
Make sure that the PTO clutch is disengaged, after which adjust the lever of the mower deck to its lowest possible position.
Your mower’s PTO clutch is tucked away in a compact bell housing. Clean the in and around the PTO clutch with a wire brush, and remove the adjustment bolt holding the clutch in place. Replace the clutch and reinstall the parts.
5. PTO Clutch Wires aren’t installed Properly
If you’ve changed the belt recently, make sure that you haven’t interfered with the wires that run from the power take-off system.
Pro Tip:That belt sometimes can rub on the wire and wear it out. Additionally, if you have uninstalled the PTO clutch, check to see if you’ve aligned the steel retainer bolt properly.
This bolt is located in the alignment hole of the PTO clutch and prevents the clutch from springing when disengaged.
6. Defected Starter Solenoid
All riding lawnmowers are fitted with a starter solenoid, which is designed to receive an electric current from the battery and send it to the starter motor.
If you have a faulty starter solenoid, it can cause the PTO to malfunction and blow a fuse.
Pro Tip:You can however test the starter solenoid yourself by turning on the ignition key, touching the two terminals with a screwdriver’s shaft, and checking if the engine starts. If it does, the solenoid is defective and should be replaced.
In the event this happens, I recommend having your mower looked at by an official dealer to determine the root cause of the issue.
Replacing a Blown Fuse
Once you identify the reason why the fuse is blowing when the PTO is engaged, you’ll have to replace the fuse.
Makes sure that you replace the fuse with the exact size as the one you removed. Most lawnmowers are fitted with a 20 amp fuse but refer to your owner’s manual for the right size for your mower.
You can install a higher rating fuse such as a 30 amp with a 15 amp fuse, and the fuse won’t blow but the fuse will blow prematurely if you install a lower amp fuse than what’s in your mower model.
Why does my mower keep blowing fuses?
There are several reasons why your mower is blowing fuses such as a temporary electrical surge in the wiring harness and/or as a result of a direct electrical short somewhere in the electrical system.
Why won’t the PTO on my mower engage?
The most common reason why your PTO won’t engage is that it isn’t receiving enough power. Further, the clutch may be worn out, in which case it must be replaced.
How do you fix a fuse that keeps blowing?
To fix a fuse that keeps blowing, check for overloaded circuits, confirm what’s causing the blown fuse, and that you’ve installed the right fuses. Fix the problem (s) and replace the fuses with the same power fuses.
There are plenty of reasons why your mower blows fuse when the PTO is engaged but the common cause is a short circuit typically in the PTO clutch system. If the above solutions don’t fix the issue, speak to your official mower dealer.
I’m Bryan Livingstone, a farmer with 21 years of experience, and I founded FarmingHandbook.com to share the wisdom I’ve gathered. Inspired by my own handbook, this site is your ultimate guide to all things farming. Read More!