CJS

Riding mower blade/PTO issue

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7 posts in this topic

Thanks in advance for reading all this and for any advice you can give. 
 

I got a free riding lawnmower about 3 years ago and I have been nursing it along for years. It is a Gravely zero turn from the early 2000’s. It ran good all summer then one day it started this deal where it would die with the blades engaged. Seems like I have a problem every year, but it’s always something fixable and 20 year old mowers need stuff replaced or fixed. Ml was Right now I am at a loss and wondering if it’s over and it’s time to give up.
 

The mower starts right up and runs fine but when you pull the PTO switch it dies. No real sputtering or choking like it’s struggling for fuel, just dies. I replaced the PTO switch that was about 2 years old. It ran one or two weekends before it started to fail again with the blades engaged. When I jumped the seat switch, it ran to cut about 3/4 of the lawn before it died again. I have been messing with it with the seat switch jumped, but just put a new one in. I checked continuity on all the switches and they all seem good, including the old ones that were replaced. Have not checked any other safety switches. 

 

YouTube pointed me towards bound/seized pulleys or PTO clutch issues as potential issues for this problem. 
 

This afternoon I pulled the belt and checked all the pulleys on the deck. They all spin free with no noise or dragging. The deck is clear of debris. It doesn’t seem to be a deck/blade issue. 
 

On to the PTO. When you start the motor with the belt off the PTO pulley then pull the switch, the engine dies. The resistance on the PTO is 2.9 ohms and YouTube says between 2 and 4 is right so it doesn’t seem like an electrical short. With the key engaged, the PTO switch wiring harness is sending 12.3 volts to the PTO. So it’s getting power. 
 

I pulled the PTO off the spindle to check if it spun freely. It has a little drag, but it doesn’t seem bad to me. I connected the harness back to the PTO but didn’t put it on the spindle and started the mower (with the seat switch jumped), the PTO clicked on and off several times without killing the engine. On the 5th or 6th cycle the engine died. I put the clutch back on the spindle torqued it down, ran the belts through the pulleys, and started the engine. When I pulled the clutch the blades started turning like they should. I started it up and cycled the blades on three times. With the blades running I pushed down the pedal to raise the mower deck (it was all the way down to pull the belt) and it stalled. Now it will start but dies when you pull the switch. 
 

My hope is that a new clutch will fix this, my worry is that this is some other electrical ghost that will cause a failure even after getting a new $150 clutch.


Does anyone have any advice with mowers that will give me some confidence it is worth buying a new PTO clutch or just show me where I have screwed this up elsewhere???

 

Thanks again for reading all that. I appreciate any help I can get. 
 

CJ

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Far from being a mower expert but it sounds like an electrical issue more than a mechanical one. The fact that pto was killing engine with no belt on it makes me believe that 

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39 mins ago, ted527 said:

Far from being a mower expert but it sounds like an electrical issue more than a mechanical one. The fact that pto was killing engine with no belt on it makes me believe that 

That’s kind of where my head is. I am not confident I am in a part swap fix kind of situation. Electrical ghosts are the worst. 
 

Hopefully someone has been here before and knows the secret. 

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Posted (edited) · Report post

When dumb **** happens it’s always a ground. Now I’m sure it’s not mechanical  but one thing to check is the pulley spindles and the pulley holes. I had a mower that kept slipping and flopping the belts because the pulley holes elongated and the spindles worn to an hour glass shape where the elongated pulley holes turned on. They appeared correct but were very sloppy in operation. 

Edited by poopdeck

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Posted (edited) · Report post

Mid October we had the lawn aerated and I didn’t mow for a month or so. Haven’t touched the mower since I put it in the shed and was dreading push mowing the whole lawn again.
 

Last weekend, I started the mower and backed it out of the shed. Engaged the blades and mowed the whole lawn without any issue whatsoever. Can’t explain it but I’ll take it.

 

At least nOw I don’t have to cuss the damn thing again until spring. 

Edited by CJS

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