The old throttle control:
The throttle control we had been using for the EA system was a hall effect thumbwheel made by OTTO. It is based on a hermetically sealed solid state device which proportions the controlling voltage output according to the position of a small magnet which is encased in the thumbwheel. The only moving part is the plastic thumbwheel, and it has no wires connected to it. The wires are connected to the sensor which is fixed in the case.
This is a flow-through design, which means that it needs no rubber seals - water can just flow through it, theoretically without doing any harm. It is rated for IP68 exposure, an international standard that represents extreme immunity from problems caused by water or dust. The manufacturer claimes that this control is made for demanding industrial and military applications.
Unfortunately, the manufacturer's claims are misleading. The electronics are sealed and protected, but the magnet is not. The material used for the magnet corrodes rapidly in contact with water. The OTTO controls we used became inoperative after a couple of seasons, even when exposed only to fresh water. OTTO refused to acknowledge this defect, instead saying that their claims of IP68 protection referred only to the sealed electronics and not to the control itself.
EALLC does acknowledge this defect and we are prepared to replace the OTTO control for all our customers.

The new throttle control:
Our new throttle control is based on a Honeywell hall-effect rotary position sensor used in the automotive industry. We currently have a working prototype in the shop. A further description and photos will be posted soon.