Happened today. Let me start off by saying that it ran great last week. It's a Exmark Lazer Z HP 23hp 52". Last day I used it was Friday. Everything ran perfectly, the way it has since I bought it. I bought the mower August 2005. (Ironic how the warranty runs out huh) It now has right at 500 hours on it. Most of them happening this year. I get on it today, and the battery is dead. First time that's happened. I carry a small jumper, so once I jumped it off, I hopped on it to do a yard. I cut the blades on, drive about 1/4 pass, and the mower cuts off. So I check gas (level's fine), and jump it off again. This time, I cut the blades on and once the blades get up to speed, the mower begins to shut off. I then push the blade switch back in, and the mower runs fine. I did this several times. The mower will not run with the blades on. I know the parking brake is linked to this switch, but so are other things, and I would think if something was amiss there, then other things would not be working right. Could it be the PTO switch itself? Any ideas? Remember, it also sucked my battery dry over the past two days, whatever it is.