Holley carb issue?

Hmm not sure whats the cause may be some of you know?
I can easily fire my engine up it runs for a 30 seconds or so and sounds good then dies then will not start again untill I manually pump the the throttle linkage on the carb and again it will fire right up? if I try to keep it going it bogs and stalls.
I replaced carb intake gasket thinking maybe vacuum leak? and checked that all vacuum lines not being used are pluged up there is plenty of fuel from fuel pump i can see it in the clear filter i used and out of the squirters on the holley 600 mechanical dbl pumper.
I wish i had another carb to use but unfortunately i don't.

Any suggestions greatly appreciated!