my metering head only needs the ingnition to be on to give fuel if you push down on the flap, no need to crank the engine on mine.

i had the same prob sime, but mine was an air lock, garage disconnectrd fuel lines to do some other work and called me in when it wudn start, we had fuel to the head an away from it,

but i removed some of the hoses and pissed about for a bit and had fuel comin out of it then, firm flap too