Fixed a small hole to set empty tank over winter about 4-5 months,
crank to have no gas come
out from manchanic fuel pump outlet pipe after fill about 5 gal gas
into tank. fuel guage showed
about one-third scale. either no gas come out from inlet hose (Fuel
tank outlet pipe) or a new
fuel/pump replaced. blow air to the inlet hose to hear bubble sound
from tank filling hole, suck gas from new pump outlet is ok ( about
15-20 psi or more ). should gas will flow to come out
from tank to inlet hose ( before f/pump ) freely because fuel pump is
about 5-10 psi working
pressure. any suggest ? Thanks.

Here's a guess, the rubber fuel hoses could be collapsing under suction,
on a car that old, I'd pull the float, and replace the " sock " filter
as it could allow air to pass, but is gummed up, and won't allow fuel
flow under high vacuum [ pump pulling fuel from tank ] conditions.