I am brush hogging the pasture, spent a few hours on the tractor. I went back to the shop to fuel up and check things over since it was the first use of the brush hog this year. Went through the normal actions, throttled down and disengaged the PTO. When I got off the blade was still turning and the kill switch had not activated. I checked and sure enough when I dismounted I must have nudged the PTO lever just a bit, enough to start the PTO but not enough to engage the kill switch. So a warning to other B2650 or similar units, no matter if you are tired always pay attention to your dismount.