Your seat switch is bad, misadjusted or unplugged.

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This post was edited by bill_kapaun on Mon, Oct 21, 13 at 21:30

I'll take a look at it. Can it be bypassed to see if that is the issue. It starts when I'm sititng but not if I'm off the tractor.

It can't be bypassed "legally".
Study the schematic.
ANYTHING that grounds the "M" terminal of the key switch will kill spark.
Disconnecting the seat switch plug also grounds the "M" terminal.

Of course it doesn't start if you aren't sitting in it! If it quits running when you get out of the seat, why would it run if you don't get into the seat?

You already HAVE tested the seat switch! When you stated that it runs until you engage the PTO or let up on the clutch.
The seat switch is not working, so the safety switch logic is that the seat is not occupied when the PTO is engaged or the clutch is let up. Neither of those actions can be done if the seat is not occupied. Even before you engage the PTO or let up on the clutch, the seat switch is telling the safety interlock system that the seat is not occupied, but it does not stop the engine because it is OK for the engine to run with an empty seat so long as the clutch/brake is down, and the PTO is not engaged.
Nothing more needs to be tested, you already tested it.

OK. I'll check the seat switch. It's a little confusing to me because if the tractor does not start if I'm not sitting in the seat, then it would appear the switch is working, but you're saying that the switch does not work. At this point is it a simple replacement of the switch?

Are you depressing the brake/clutch when you are attempting to start it when not in the seat?

AGAIN!
"Your seat switch is bad, misadjusted or unplugged."

A "simple replacement" won't do diddly if the adjustment is wrong.
Make sure the plunger is getting depressed enough!

The switch must be OPEN for the tractor to run. When NOT in the seat, it's closed.

Got it. I'll check the adjustment first. What is the procedure to do this?
Is there a manual/schematic for this tractor online I can download?

IF it's an adjustment issue, you'll have to try to move it so the plunger is more depressed when on the seat.
I've heard of some people actually haveing to shim it with a slice of wood or similar.

Schematic is in the owners manual-
http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0409540.pdf

Here is a link that might be useful: Owners Manual

Thank you very much for your time and patience. I will let you know what happens after I take a look at tractor. Probably this weekend.

Well, I was able to work on the tractor and got it working
100%. You'll never guess what it was. The seat switch needed adjustmen! LOL. Thank you so much Mownie and Bill for all your help! I haven't been able to use tractor all summer, now it's up and running in time for leaves! Thanks again.

BTDT! Glad you fixed it..