An electric lawnmower clutch, or a PTO switch, is a safety feature that turns the mower’s blades on and off. Manufacturers like John Deere, Cub Cadet, Ferris, and other riding mowers all have the same basic feature on their models. When this essential part of the mower machinery isn’t working, you’ll want to inspect it immediately to see what the problem might be so you can get it fixed and get back to your lawn care routine.
From wear to damage, a few things may be disrupting your connection between the switch and the blades, resulting in the blades shutting off or not connecting in the first place. Knowing what to look out for will help you be prepared in case your PTO switch stops working.
In This Article
What Does P.T.O Stand For?
PTO stands for ‘Power Takeoff,’ referring to the clutch that engages the rider mower’s blades.
How Do You Use A PTO Switch?
When you engage the PTO switch, it actives the clutch (the mechanism that connects and disconnects engine power to a part of the machinery) for the mower blades. When you disengage the PTO switch, it disconnects the power to the blades, and the mower stops cutting.
The PTO switch is a connector, having metal prongs that provide the medium for the current to flow to the mower blades. As a safety feature, not having the mower blades on at all times, especially at homes with children and/or pets, decreases risks associated with blades that run whenever the mower is running. This feature allows users to disengage the blades if they want to drive their riding lawn mower as a tractor to pull other equipment.
What Happens When A PTO Clutch Goes Bad?
After a while, the PTO connection may start to wear down. When the PTO clutch goes bad, the blades will either shut off during use or not start at all. If you’re trying to mow your lawn, you’ll want to inspect the connection immediately to diagnose the problem.
Generally, the problem will be that power isn’t flowing between the switch and the clutch due to an interruption at one point or another along the connection between the engine, the clutch, and the PTO knob. Taking a look under the hood, you’ll be able to check the various nodes for a sign of damage or disconnection.
Why Does The PTO Not Engage?
There are several reasons that the power may be interrupted along the PTO connection:
- Corrosion or debris in switching mechanism – The PTO switch is a pull-knob usually made of plastic, and the internal switching connections are made of metal prongs and brackets. Over time, the plastic will wear down and may build-up, and the metal may get wet and begin to rust or otherwise corrode.
- Blown fuse – If there is a failure along the connection, the associated fuse on the operational panel will be blown out, and the connection interrupted for safety. This may be caused by too high of voltage being received due to frayed wires, exposure to moisture, or another connection short.
- Frayed or exposed wires – Over time, the plastic insulator coating on the copper wires will wear down and may expose the wire. When that wire comes in contact with a conductor like moisture or an organic material, it will short the connection and may blow a fuse or heat up the switch, becoming a fire hazard.
- Burnt out switch – A switch can get damaged by a short in the connection. The plastic connector may melt or heat the metal excessively, damaging the switch and disrupting the flow of power.
- Connection was bypassed – Some skilled riding mower owners interrupt the PTO switch connection intentionally and at their discretion. A bypass of the safety feature may be done by users who don’t have children or pets around, don’t drive their mower as a tractor, want the blades on always, or have other reasons particular to them. If you purchased a used model and your PTO switch isn’t engaging, the connection may have been intentionally bypass
How Do I Know If My Pto Switch Is Bad?
If the engine is running, but the blades won’t engage when you’re pulling the knob, then you know the interruption isn’t due to a dead battery. You can remove the switch from the dashboard panel to inspect the controller itself and check the connected wires and the clutch at the base of the mower to see which node in the system may be the dead end.
How To Test A Pto Switch
Your PTO switch can be tested for connectivity using a multimeter, a tool that measures electric currents and conductivity. Below the knob on the switch, there are 3 rows of prongs that are the electrical connectors for the on/off settings. When the switch is off, it won’t allow electricity to flow, but when it’s on, the switch opens the connection, and the blades can receive energy from the engine.
You can use the multimeter to test the on-position and see if the middle and bottom row of prongs permit an energy flow. If not, the switch needs to be replaced. This can easily be done by purchasing a new switch and connecting it. Using dielectric grease on the metal prongs will help insulate it from moisture and corrosion and can extend the life of the switch.
If the switch is functional, the problem is a disruption in the connection elsewhere along the line. In this case, follow the wires connected to the switch down to its connection to the engine and clutch. Gently testing the wire connectors with the multimeter to see if voltage is flowing through it will identify where the disruption or damage is.
Even if the switch seems to be damaged and the point of disruption, you should check the connections along the line for any voltage amplification or damage that may have shorted the switch, fuse, or other node in the connection.