Gravity flow through the one way check valves in the pump toward the carburetor doesn't necessarily mean it's bad, as long as they seal going the other way. Doing the fuel pump volume/vacuum/pressure test that I've been recommending for years is the right way to check a pump, but to the best of my knowledge, nobody has ever bothered to listen to me on that one!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!