My fuel pump for the BA-6 system I have (on my '65 deluxe) came with
a stuck fuel pump.  Apparently it was stuck open as black smoke was billowing
out the last time the PO had it going.  The pump werks kinda like a solenoid
that is actuated by the rotation of the unit's blower motor.  Every 33 1/3 (?)
revolutions, and the pump clicks open-closed.  I removed the pump, disassembled
it as per Tim Smith's suggestion, removed the screen, found a small diameter
impliment to push/free up the internal piston of the pump.  While it was out
I tested it with a 12V batter by touching the connections to the battery 
terminals.  Hook up the negative terminals (bat/pump) and tap the positive
lead on the battery's positive terminal.  The pump should click for every
tap...

christian