I have a 6 year old Craftsmen Garden Tractor, model 917.275287 and yesterday while mowing, the mower deck disengaged. No weird sounds, no odd smells, etc. I removed the mower deck and all the belts and mandrels are fine (and now, nice and clean!) so it was off to the Internet to search for possible answers when I found Garden Web and this looks like the place to be!

After reading through some of the posts on PTOs and similar problems, I see that the most likely culprit is probably the PTO switch, then maybe the ignition switch (the fuse is fine). I'm thinking about ordering both parts as, at about $50, it's still a lot cheaper (and probably faster) than trying to get it serviced. I don't mind having a few spare parts lying around anyway. Does this make sense? Are there any tests or inspections I should be doing first? I have 5 acres to mow so I can't dilly-dally around too much - just grateful that it did this in August and not May!

Thanks!

But, if you can't get 12 volts on the red wire, your PTO switch is the most likely culprit but you still need to check for 12 volts being present at the input side of the PTO switch. The terminal on the PTO switch to check for 12 volts when the key switch is in RUN position is labeled "B".
With the key switch on, you should be able to detect 12 volts at terminal B on the PTO switch. Next, engage the PTO switch, now you should be able to detect 12 volts at PTO switch terminal E.
If you detect 12 volts at B but not at E when the PTO switch is engaged, replace the PTO switch.
If you DO NOT detect 12 volts at terminal B on the PTO switch or at key switch terminal "A1" when the key switch is at RUN position, replace the key switch.

I have included a link to the Sears direct site for your owner's manual.
Click the link to go to the website, then click "view manual" to download it.
I suggest you save a copy to your computer for future offline reference.
The manual includes the wiring diagram for the tractor.
Refer to it when doing the testing above.

Thank you! I will do just that. Unfortunately, it will have to waiytt until the weekend due to my work schedule this week, but I will post again when I check it out. I still have my hard copy manual, but it's nice to have a PDF version, so thanks for the link!

So I guess I better start with the basics! I assume this is the pigtail to unplug below:

Can you tell me how to unplug this without damaging the wires? I assume it has a catch release or something. Just pulling on it didn't work and I don't want to make matters worse!

Strike that last post! I had t get under the tractor to get enough leverage to get the pigtail apart. Now on to the next step. I am getting 12 volts from the from the switch red wire and I heard no click when I reconnected the pigtail with the power still on and the PTO switch still engaged. Next I had my wife start the mower and engage and disengage the PTO switch while I watched the pulley under the clutch. It does not spin, but the bolt and shaft it is mounted on spins constantly (PTO switch engaged or not). Does this narrow it down to a bad clutch?

Walt Conner
wconner5 at verizon dot net

Unless you have an impact wrench (electric or pneumatic), getting the PTO mounting bolt out (and tightened later) can be a bit challenging.
In lieu of an impact wrench of your own, you may want to try the "poor boy's" impact method as follows:

Safety glasses or goggles should be worn when doing this, or any time you are under the tractor messing around.
Hold a "6-point" boxed end wrench on the PTO mtg bolt with a gloved hand by putting the hand (or just a thumb) over the end of the wrench where the PTO bolt is. DO NOT hold the wrench by its handle end. Take careful aim and smack the free end of the wrench with a hammer, hitting it in the direction to loosen the bolt. Keep the wrench pressed tightly in place on the bolt head when you strike the wrench. When the bolt has loosened, you can spin it out with the wrench or your fingers.
BEWARE! The clutch is fairly heavy and if you are not careful you might get a surprise when the last thread of the bolt is turned.
When mounting the new clutch, use the same "wrench & hammer" technique to secure the mounting bolt.

Or......ask a friend to use his impact wrench.

A third option is that you could remove the "fan & flywheel" cover from the top of the engine and hold the large flywheel mounting nut to keep the engine from turning when you loosen and tighten the clutch bolt, but that means it will be a 2 person job, and with bigger tools needed. I don't know if you have the tool or personnel resources.

OR if your are even more unlucky, the clutch may have grown fast to the crankshaft.

You can hold the engine from turning by removing the spark plug and threading in a ft. or so of 1/4" or so nylon rope making sure to turn the engine where the valves are closed first.

Walt Conner

Yes, I do have a camera and learned to use it often when messing around in the garage. Saved my butt when I rebuilt a carburetor and tried to remember how to get it back on the snow blower!

I'm checking with Walt on the clutch and that'll give me time to decide if I want to take it on myself or get someone else with the right tools to do it. I also don't have anything to jack up the tractor on. Do you think I can do this without getting it up in the air?

Yeah, but easier if front of mower lifted a ft. or so.
Since my clutch wouldn't fit, check on eBay, SOMETIMES there are good prices on clutches there, sometimes not.

Walt Conner

Actually, it was a piece of cake. I didn't need an impact wrench at all but I did borrow a set of ramps from a buddy and that made putting the clutch back on a little easier. I used the third option suggested by Mownie and just had my wife hold the flywheel with a wedge while I loosened the bolt. It came off very easily and took just a few minutes to swap the old one for the new one. While I had it part I replaced the drive belt too and that actually took longer than swapping out the clutch!

Another benefit was I found an online source for parts for my tractor that runs about 30-50% less than what Sears charges. I can't believe how much I could have saved over the last 6 years on maintenance parts alone!

Thanks so much, Mownie and Walt! The repair was minor but I might not have tried it without the confidence provided by being able to 'consult' with you guys when I had a question.

The ground circuit for the PTO is switched.through the Operator Presence Relay.
The ground lead connects to pin 87.
Pin 87 is switched to ground when the seat switch is closed (occupied) and 12V delivered to pin 85 of the relay.

You might check to see if the ground lead of the PTO pigtail is being grounded when the seat switch is operated.
(Key & PTO ON)