Fuel selector

The original fuel unit I have very limited knowledge of and cannot recall the detents in looking at the IPC. Starting with D2901, and possibly installed to earlier aircraft as an improvement, the detents are external on the top of the assembly; as such, the depressions the balls ride in can fill with debris which will soften the 'detent action', and should be periodically cleaned.

The way to tell the difference from the pilot seat is the early units used the selector valve handle as the hand pump actuator (as well as an indicator light on the instrument panel to tell you the selector is not engaged), the later ones have a second lever that is stroked for fuel pump action.

Mike
ABS Tech Advisor

Thanks it must be a later one as it has the lever for the pump

The detents should be positive. The pump-selector assembly is not hard to reseal. Too many airplanes run out of fuel with lots of fuel on board.