The pump should kick off no matter what you prop the handle with given it is just another stop like the one on the handle. It does bring up an idea. Each pump handle seems to have its own rate. If we made up a little stop gizmo that was adjustable you could fine a sweet spot with maximum flow and let it run. Many times I have almost made the second handle notch stop work only to have to resort to the slow rate of the first notch to keep the pump running. Something to consider...
Later Ed