View Full Version : PTO Clutch Life Expectancy

04-24-2010, 10:35 PM
I have two Exmark Lazer Z XS mowers. One had a clutch go out at 300 hours and the other now at 600 hours. Isn't that kind of early? What do you guys normally get in hours out of a pto clutch. I have a employee that has engaged and disengaged at full throttle. Would that effect them to the point they fail at these low hours?

04-24-2010, 10:51 PM
It definitely would decrease the clutch's life to be engaged at a higher throttle than intended. I find that it actually is smoother to engage at 3/4 throttle anyway.

04-25-2010, 08:31 AM
Your manual should tell you the proper procedure for your mower. Here is what I've been told: engage the blades at high enough rpms to not bog the engine and shut off the blades with the engine at idle. The idea is to minimize wear on the brake that stops the blades. One of the things that kills clutches is heat buildup. One way to tell if the clutch in a mower is getting "worn" is to observe how long it takes for the blades to start after the knob has been pulled and also how long it takes for the blades to stop after the knob is pushed. The brake pads on a clutch can be replaced with a kit which will greatly lengthen its life. I've had that done several times on full size tracers.

04-25-2010, 07:33 PM
Engage PTO @ 3/4 throttle or so is a good idea, I throttle up immediatly after I engage the blades - running the engine at low idle with the clutch engaged will wear the crap out of your engine. The number of on and off cycles will affect the number of hours. If I'm constantly engaging & dis-engaging, the PTO life expectancy is reduced. I see some guys disengage the clutch crossing a driveway... some will say you should, but if there is no debris on the driveway, I say keep it cranking. Having a mulching deck also helps me not to worry too much about throwing a rock or a small pet. Seems I only replaced the clutch once... the OEM had just under 2,000 hours.

04-25-2010, 07:56 PM
Most owners manuals will advise you to engage the PTO at 1/2 to 3/4 throttle and then move the to full throttle once engaged. Alot of people don't take the time to read the owner's manual and will engage the PTO at full throttle.

Disengaging the PTO also should be done at lower RPM's.

The more you turn the PTO on and off, the less life you will get out of your PTO. I try to keep the PTO engaged throughout an entire lawn, the more times I have to start and stop the PTO the sooner I will have to replace it.

My bobcat was still on its original PTO when I sold it and it had 13XX hours on it and still working fine.

04-26-2010, 10:15 PM
If you are cutting big tall wet grass and running fast they will wear them out.