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Toro 266H Year: 1994
Model: 72083 s/n:4901032

Kohler Twin V CV16S
Spec: 61514 S/N: 2408009097


Hi - My first post.

I have been cutting grass with my Toro since 1994 - about 900 hours. Other than belts, never had a problem.

Last week, in the middle of a cut, the mower died. Troubleshooting showed the 30 amp fuse was gone, and the PTO switch was not making any of the proper contacts - "1" and "3" were always OPEN (safety), "1" and "2" were always OPEN ((PTO Engage), regardless of whether the PTO switch was pushed IN or pulled OUT.

I bought a new PTO switch and replaced the 30 amp fuse. The Toro started immediately, and I began to cut grass. After 20 minutes of easy cutting, it died again. The 30 amp fuse blew. The new PTO switch checked out perfectly. I changed the fuse again, and it wouldn't start. I could not detect that any dash lights were on. I jumped the starter, and it would not start.

(The battery is brand new, and checks out at just under 13 volts. Battery connections are good at the battery and engine ground end.)

Just for the heck of it, I tested all 4 relays - they all checked out.

I'm wondering about a short somewhere along the wires powering the PTO, or maybe the PTO is drawing too much current when it gets hot after say 20 minutes of use.

1. Does it makes sense that the PTO clutch will work for a while, and then draw excessive current to blow the 30 amp fuse?. It currently has an impedance of about 2.5 ohms. I priced a new PTO clutch, and I was quoted $800 Canadian. If true, this is insane.

2. What would cause the PTO switch to go? Just age and and too much current draw?

3. Could this be an ignition switch problem?

3. Any other ideas that would cause this problem?

Note that the deck is in good condition, I can move the belt by hand easily, and all the bearing were AOK as of a month ago. Nothing is binding. The grass barely needed cutting, and the ground is fairly level.

I will try jumping the starter and starting it tomorrow. (I was able to do this successfully the first time the problem occurred.) I will also look for a short tomorrow.


Thanks


M...

:welcome:

1) yes they get hot, heat increases the resistance which draws more power which increases the heat in a self perputating loop till the fuse calls it quits.
PTO clutches are expensive. Try some aftermarket suppliers you might get some down to 1/2 to 2/3 of that price.
2) yes they are just simple blade contact switches, they corrode, get full of dust , burn at the contact point and even get full of ants.
3) Yes, all power goes through the ignition switch ( except cranking power obviously ) and it is not much more robust than the PTO switch

PIA when this happens.
If you are electrically savvy then power the clutch through a relay and just use the PTO switch to energise the relay as 30A relays are around $ 5.
You can even shop around a bit and find relays that have a blade fuse built into the relay holder thus if the clutch blows the fuse you can still drive it back to the shed.

The PTO switch & seat switch are connected to the magneto cut out
The brake lever and the seat switch are connect to the magneto cut out on a seperate circuit.
The PTO switch , ignition switch and brake switch are connected to the starter solenoid in a daisly chain

Hi.

Thanks for the response.

I took the bad PTO switch apart with a Dremel tool. Cheap design in my mind - but it did last 22 years. A copper u-shaped contact strip that moves up & down as you push/pull the knob looked worn, but no sign of arcing as I would have expected. No sign of ants lol.

What are the odds that the PTO switch goes, and then the ignition switch goes? Murphy's law I guess. Maybe the heavy current draw of a short is destroying them. I will check out the ignition switch and look for a short tomorrow.

1. Do you have a part number for the clutch/pulley assembly? Perhaps the clutch is separate from the pulley.

2. You mentioned after market suppliers - will they have direct replacements?

3. Do you have any links to suppliers that would carry the part?

4. Is the clutch/pulley assembly held on by just the centre bolt? Looks like a simple job to remove. I just want to ensure I bring the right tools with me. The problem is that the tractor is a 60 mile round trip away.

I am electrically savvy, and I have the infamous Demystification Guide.


Thanks so much for your advice.

M....

Mike Green said:

Hi.

Thanks for the response.

I took the bad PTO switch apart with a Dremel tool. Cheap design in my mind - but it did last 22 years. A copper u-shaped contact strip that moves up & down as you push/pull the knob looked worn, but no sign of arcing as I would have expected. No sign of ants lol.
There was a case a while back wher ants got under the contact, true, and yes it is cheap & the new ones are even cheaper

What are the odds that the PTO switch goes, and then the ignition switch goes? Murphy's law I guess. Maybe the heavy current draw of a short is destroying them. I will check out the ignition switch and look for a short tomorrow.

1. Do you have a part number for the clutch/pulley assembly? Perhaps the clutch is separate from the pulley.
No I will need the model number off the tractor to find that out and there is a slight chance a unit that old is a 3 piece clutch , modern ones are 1 piece & not servicable
2. You mentioned after market suppliers - will they have direct replacements?
Warner, Ogura & Bosch supply the clutches
3. Do you have any links to suppliers that would carry the part?
Click on the word "Parts" in white on the top green bar, I use jacks most often
4. Is the clutch/pulley assembly held on by just the centre bolt? Looks like a simple job to remove. I just want to ensure I bring the right tools with me. The problem is that the tractor is a 60 mile round trip away.
Yes one bolt, sometimes they can get sticky but don't stick your head under it & pull they are heavy and come off fast:mur: Usually 5/8 or 9/16 and a deep impact driver & socket works well.
Undo the wiring plug first and on some the stay has to come off as well, if so take it off first.

I am electrically savvy, and I have the infamous Demystification Guide.


Thanks so much for your advice.

M....

Click to expand...

Answers in red

Hi.

I have A kohler Service manual. It appears that the clutch assembly is p/n: 92-6885. It also shows a "Field" component that is screwed on with 3 screws/nuts: 92-3016. I wonder if the "Field" is available as a separate item? The "Field" is shown with a wire coming out of it, and would be all I would need.

The Clutch 92-6885 is shown as 3 parts:
Rotor ASM with bearing
Field ASM with bearing (92-3016)
Bearing

If I can't find a short in the wiring, I will bring the PTO home to test as follows: I will hook it up to a 12 volt power supply with an in line 25 amp fuse, and leave it plugged in overnight and see if it blows the fuse. Does this make sense to you?

I will keep you posted.

Thanks,

M...

Hi.

And the plot thickens.....

I went to Jacks and found the PTO ASM 92-6885 for $419 US. This is actually cheaper than the "Field" component which they want $495 US.

Then I went to Amazon:
https://www.amazon.com/Replaces-92-6885-Clutch-Torque-Bearing/dp/B00YQ8H3JS

and this aftermarket one is $189 US. Much easier to swallow, So my next question is - do you have a problem with the Amazon choice?

FYI: I would have to add about 40% to my Canadian dollar to equal your US dollar, so the $189 US Amazon would run me $264 Canadian. I can handle that.

What do you think?

Thanks,

M...

I have heard good things about that brand. I would purchase it.

Hi.

The latest update for anyone interested:

Thanks to this forum, I have resolved the PTO clutch problem on my Toro. I bought the following PTO clutch from Amazon:

Replaces Toro 92-6885 PTO Clutch with High Torque & Bearing Uhprade – From Xtreme Outdoor Power Equipment
https://www.amazon.com/Replaces-92-6885-Clutch-Torque-Bearing/dp/B00YQ8H3JS


A Toro direct replacement clutch in Canada is $839. The US counterpart sells for $419. (Currently there is a 40% exchange rate for Canadian to US dollars). The Xtreme replacement is $190. A no brainer.

This is a SUPER replacement part that fit my TORO perfectly. I have done many lawn cuts with it, and it has performed flawlessly.



I do have some comments on the install:

Using a pipe wrench (a vise grip would do), I held the Kohler output shaft in place and torqued the PTO nut to 55 ft lbs. As per the instructions, I burnished the clutch some 21 times by engaging and disengaging the PTO.

The connection wire was a few inches shorter than the original, so I had to add an extension.

Getting the clutch aligned and bolted on was NOT easy. It is fairly heavy, and trying to line up the clutch with the the Kohler output shaft took quite a while. I finally had to jack up the front of the tractor.

If doing the job again, I might get a length of 7/16 X 20 threaded rod and screw that in to the Kohler output shaft.
Then I would fit the PTO into that and push it up against the output shaft. I would then lightly snug up a washer and bolt onto the threaded rod. This would take the weight off the PTO, as well as make a perfect alignment. I would then turn the PTO while pushing up until it fit into the keyway. While holding the PTO in place, I would remove the threaded rod, and screw in the proper bolt. Sounds like a plan


Thanks for all your help.

M...

Thanks for the follow up very few have the common courtsey to do that.
A bit late now but I stand the mowers on their bums when doing clutches, much easier when everything is in front of your eyes rather than falling into your eyes.
Thus the clutch slips on and stays there.
Just be sure the petrol is not going to pour out of the tank & if you are going to leave it standing up for a long while, take the battery out, some "sealed" batteries have an overflow.