Fwd: Fuel system woes, again..

[CALXA]

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Title: Re: Fuel system woes, again..

Jerry, the gaskets need to be tight to prevent siponing (sp), and the cap
should have a hole in the forward end, so relative air pressurizes the tanks.
There is an emergency cutoff valve inside the cabin - right lower side ( to
only be used in emergency, to cut off fuel to engine compartment incase of a
fuel line failure, etc.) Make sutre it is open. If the fuel pump is working,
and the airplane has been setting allwinter - several months, you may have a
build-up of gasoline deposits -crystalline- stoppoing up the line from the
fuel pump to the header tank.. Check for being open..

One failure I have seen - over and over is that after the strainer screen in
the fuel pump is checked/changes as per AD, the top cover of the fuel pump is
not securred properly.  This situation allows air to be sucked into the pump -
instead of sucking fuel from the rt. tank, and delivering to fuselage tank. If
pump is working oK, trace lines to be sure you haven't crossed them - suction
-vs feed - , and that they are clear.

While the pump may be pumping fuel with hose off, it may not be sufficient
force to pump the additional 8 inches of head. Check this by placing a hose on
the pump output, and raising the end to the level of the header tank, and also
check pressure.
I don't remember the pressure, but probably 5-7 psi. There is a restrictor on
the output side to limit the out put to about 7 gal/hour rate. Be sure this is
not restricted, and is in place. Otherwise the fuel pump will overload the
header, and raw gasoline will overflow the header tank cap - not nice.

Hope this helps - Its hard to imagine that low pressure on the top of the wing
would form a partial vacumn, preventing the fuel pump form operating - unless
it can suck in air somewhere else ( the fuel pump cover being too loose).

Regards

Fly Safe - Have Fun

Harry
93530
BCB

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