You were correct. This was my shut off solution. On the left side of the bagger, facing it from the rear, there is a safety switch that needs to be engaged. It is finicky, if it is not depressed fully, mower will stall while trying to engage. I solved this problem by sticking (glued) a small rubber bumper to the switch, so as to make it a more reasonable tolerance. Since then, no problems.Still works as shutoff as factory intended, but no stalls.