New Guy with Inoperable PTO Clutch on RZT50

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Doug Neal

New member
Feb 20, 2022
Brush Prairie, WA
Good morning from Brush Prairie, WA folks. New guy here who just joined up yesterday. I'm dealing with an inoperable PTO clutch on my 2007 RZT50 with 655 hours. I bought the machine used about 6 years ago with 255 hours and have been using it to mow about an acre and a half of my property. It has worked without issue until this weekend when the PTO quit engaging while I was mowing. It failed to engage once and I was able to engage again after a couple of back and forths. It did this a couple more times then quit engaging completely.

I pulled the clutch, cleaned and adjusted it, and reinstalled it. I have verified that it functions properly when powered directly from a 12 volt battery. The coils click and I can see the clutch plate move upward to engage. I measured the voltage at the clutch plug and it is showing only 4.5 volts. As I was working on it, I got a reading of 14 volts so I plugged it back in and it would operate the clutch from my PTO switch while the engine was not running. However, when I start the engine the clutch will not engage and the voltage goes back to 4.5-5 volts. I did this 3 different times although I still don't know what I did to get the voltage back up to 14 again. (It's not cooling down or disconnecting the battery so I'm a bit confused).

Admittedly I'm not a mechanic but I do all my regular maintenance, minor repairs and mods so I can turn a wrench (with instruction). My weakest area is electrical and I seem to have difficulty chasing down the gremlins. Have any of you noticed that a wire full of 'tricity looks just like a wire with none at all? Anyway I'm interested in any suggestions or input y'all might have before I take it in to the (gasp) shop. I really can't afford to be down for long. Thanks in advance for any suggestions and I'll look forward to contributing here with my strong points, mainly humor, wit and inane comments.

Cheers! Doug

Bret McFarland

Well-known member
IHCC Supporter
Jun 30, 2022
Western Maryland
Obviously something siphoning-off voltage at runtime. To help troubleshoot you could spend a little $$ to replace components that could be faulty (vs. just slogging through with a voltmeter). For a 15-year old mower that you use, it may be a good thing anyhow while you're in there.
- replace PTO switch first, this could be the issue
- ignition switch
- inline fuses or circuit breakers
And you'd be reconnecting and tightening some connections.
You also could run a separate ground direct from the PTO (may not be grounding properly at the PTO)

I am no expert! But seen this before ... too old and confused to remember what tractor I was working on :)
Last edited:


Well-known member
Apr 18, 2020
Winston-Salem, NC
I had a ZRT50 (2004?).. with an intermittant-then inoperable pto.
It turned out that the RED wire that plugs into the PTO multi-wire plug... had gotten hot, melted the retaining tab, and the wire/connector vibrated loose. I was able to get it reinstalled, and glued a small piece of plastic into the connector, to hold it in place.
I did have to remove the plastic fender to gain enough access to the plug to do the mod.