[reelapeelin]

By ''standing up''...I mean "upright"...the fuel is flowing as straight UP as you can reasonably get it...some systems are not as sensitive to this as others, but on some, it's crucial...the bulb is there to fill the hose goin' UP to the motor ... on some, gravity pulls it back down when not runnin'...if the check-valve in the bulb is workin' properly, that shouldn't happen...that check-valve generally works better in ''upright'' position (arrow indicating direction of flow pointing straight up)...if a bulb doesn't get firm, it may be a bad bulb (even new) or air's gettin' into the line somewhere...