On Mar 10, 3:21*pm, wrote:
Looking for suggestions for a aux fuel system transfer pump.

*I've only got 5-6 gal to move so don't really need anything big *I
don't have a lot of room and weight is an issue of course.
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So go down to your FLAPS and ask to see the BIGGEST manual fuel pump
in stock. For manual operation you'll want to find some lighter
springs. On some, the actuating arm is long enough so that,with the
pump mounted in a suitable position, you can put a threaded ball on
the thing and use it for the handle. Otherwise, you rig a frame to
support the pump then position & pivot a rod or shaft to use as the
pump-handle.

The problem with real fuel pumps is that their output is quite small.
At a steady 60 mph a big V8 is only putting out mebbe 30hp...
something less than 3 gallons per hour. Since an automotive pump is a
variable-output device -- that is, it's output is a function of the
PRESSURE on the outlet -- to get the maximum amount of fuel per stroke
you want to be sure you're delivering pressure into an 'open' tank.

Tricks I've seen or tried: The use of TWO automotive fuel pumps,
rigged so that one pumps on the forward stroke, the other on the aft
stroke. This thing was the closest I've ever FELT to a real wobble-
type TRANSFER pump (as opposed to a primer) in that it required only
finger pressure to deliver about 4 oz per fore-aft 'stroke'.... or
about 35 strokes per gallon.

Slightly better output (about 6oz/stroke) could be achieved using
those RUBBER primer-bulbs used with outboard motors fed by a remote
fuel tank. Rig a pair of them in a fixture of some sort that would
allow them to be mashed flat (or nearly so) by some kind of toggle-
action shoe. Definitely lighter than an automotive f uel pump but
probably more prone to leakage/wear, etc.

Why even consider pumps & primers? Because they come WITH the
required valving.

-R.S.Hoover