I asked my luscombe friend and he says the 20' 1/4" line pumps 1.5 - 2.0 gals /min using is ford ranger p/u at idle.  he keeps it coiled under the hood and has had no problems in several years of use.  there is a "T" and shut-off valve at the base of the hose.  I agree that he should be grounding it.  I suppose the liquid in the hose grounds it to the truck (if he submerges the hose), but neither vehicle is grounded to the earth (sorry, redundant).   still, a much safer system than cans of fuel.

kevin (remembering an injury on way to the airport when I had to slam the brakes and got hit with the hand truck I was carrying in back)