Just found this LEGO pump top by a well-known and very clever Japanese builder:
He's written several books full of ingenious LEGO mechanisms and whimsical machines. My kind of guy.
This one could easily be improved by lowering the CM and doubling the yellow flywheel ring.
My own attempts at a LEGO pump top all failed for lack of a suitable screw, LEGO or otherwise. Looks like LEGO now makes the screw. Off to
www.bricklink.com ....