Martin, I'm with Mitch on this one. Number one on your list is fuel pressure, verified, with an actual gauge. If possible, run a long hose and observe while you've got your foot in it(please take a helper with you to read it!).
Number two is float height.
Number three is jetting. These are all done at a steady state: i.e. gas pedal in a fixed position, whether it be cruise or WOT.
The LAST thing you mess with is accelerator pumps.
It could also be that distributor/spark thing. Most "carb problems" are "ignition problems".