Well . . just for "giggles" - your Electric fuel pump is "between the mechanical pump and your carb" ?
The electric fuel pump - - should be , back close to u'r fuel tank ; and , thus pump forward , towards the engine. Some of those elec. fuel pumps , don't work very well = having too "suck gas" that far.
I had this very same 'problem - on a 79 Ford truck' ; that I fought for over a year. I'd pull over and remove the TOP of the 2bbl carb . . . . the float chamber, would be 'dry' .
I was using those "small clear fuel filters" , too see if my fuel line was running dry . I fought this "condition" for a long time (even replacing that carb with a brand New 2bbl stock carb) .
Turns out - - - I would keep changing out - - - those clear fuel filters ; but never checked the "stock fuel filter" (that filter , that "screws-into the carb float chamber" ).
See , what I'm saying - - - I would change ONE fuel filter & not even check any other "Fuel Filters" ............................... that stock , screw-in Motorcraft fuel filter , was my "problem" .
So, make sure too "not focus" , on just one issue (meaning = Check all your fuel filters ) . What carb are you using on your 250 engine ? ?
jim
