Yes on the battery. Though you may have other issues also. Most PTO clutches won't fire below 10.5v when all is said and done. So even to begin troubleshooting, start w/ a new battery and get 12v to the clutch. Brush or otherwise clean the battery terminal ends and tighten securely. Do you have a basic multi-meter?

Did you have the entire mower covered and not setting out in the rain that way? Does your machine have slots (louvers) in the top of the hood? Did you have those slots covered from any rain that could fall in them, which would short out the ignition?
The first thing to make sure is workable, is the battery! If it is more than 2 years old, i'd suspect it to be causing problems. Next would be the connections to the battery and the starter. After that would be the fuel supply and the age of the fuel. Gas doesn't last like it did 10 years ago. A new spark plug might help, too.
A clean up of the ignition area under the flywheel tin cover, could be needed, especially if you allowed rain to fall into that area!
Rusty Jones

Your machine has a 15 AMP charging system, so at high speed, you should have sufficient current.
Headlights & fuel solenoid will use around 5-6 AMPs and PTO probably around 3-4?

HOWEVER- IF the battery is low in charge, it may "suck" a higher than normal amount and thus drop the voltage to the point that the PTO disengages.

I would start off by fully charging the battery and see if that resolves the problem (at least temporarily).
IF the battery is 2 or more years old, I'd definitely get it load tested.

As a matter of course, you should ensure that the connections to the PTO SWITCH and PTO are good.
You should unplug/plug a couple times to "wipe off" any "crud".

Don, I think tomplum & bill kapaun nailed it. I've had this problem several times with several lawn tractors and a larger CUT - a good battery charge usually takes care of the problem, but battery replacement might be required. Just because your battery will start the engine doesn't mean it's got enough "oomph" to run everything, as described by bill.

Well Don-
It would have been nice if you'd let us know what happened!

I've resurrected my do not help again list.

Bill - Have you noticed how often this happens when the poster has just signed up in the forum? I figure that most of the time the guy already found the answer and never bothered to check back. On first-day posters, I either wait a bit to respond, or ask a follow-up question, or if the answer is short just go ahead and give it ... If the problem is a complex one sometimes I get a feel that the fellow doesn't have the knowledge or tools to do the job. After all, you can't teach somebody to use a multimeter so he can isolate an electrical problem .... Ah, well.

Another excuse that I have seen put forth a few times goes like this:
"I thought I would get an e-mail to tell me if somebody posted a response to my thread/post."

Of course a poster might simply be too lazy to reply with a follow up about his findings after being advised here.

Maybe they just don't "get it" that this is a DISCUSSION forum where folks SHARE thoughts and ideas.

i am a service manager for a mower dealer i am used to never hearing back from customers about repair problems. that being said i have a problem with a 97 carftsman mower the rear axel& trans it is a 218-3010L i am looking for a hose diagram and position of pump plate.

You'd expect a "service manager" to at least identify the tractor???????????

At least as a service manager, you can pick up the phone and call the folks back and see how you did. At least on the sticky ones. That's how you learn and that's how you keep customers. Drop the # into Google. I think every tenth website has HG manuals.

I have a Craftsman GT5000 and want to raise the mowing deck. Has anyone done this and how?

homeowner1947 - I just gotta ask this - have you read your owners manual? It has detailed instructions about such, unless you are talking about some extraordinary deck relocation project...?