When you get off the seat it should kill the engine in about 5 second. If you flip the seat up before the 5 seconds it will keep running. If it doesn't kill the engine after 5 seconds I would say that the tab on the seat has been bent and needs to be adjusted. This is covered in the Operator's manual.
I bent the seat tab in towards the seat cushion. Now engine will shut off if you get off seat while moving or if PTO is engaged. If you move around on the seat engine will cut out. But I want the safety working.