How can I tell which fuel selector valve I have in my plane?
Search strings: FSV, fuel valve, valve handle
Technical Editor:
The good Gerdes aluminum valve has a smooth handle (no writing). The top of the 3/8″ valve shaft has a flat on one side, and the handle can only be reinstalled one way (the correct way).
The ‘bad’ brass Imperial valve has a thinner handle with the word ‘Imperial” cast in the handle. The top of the shaft has four flats/square shape, allowing the handle to be reinstalled in any of four orientations. There is a tiny ‘cross pin’ that has to be correctly lined up, to get the handle properly reinstalled. People frequently jam the handle back on wrong, so take care if you do have the old valve (and remove the handle).