running out of fuel with my 40mm dellortos
should the std pump keep up?
or do i need to go electric?
i get to 3rd 5000 rpm then run out of fuel
back off change to 4th and then got fuel
only runs out with 7000 rpm shifts
yet to test fuel pressure
tommo

stock pump should be up to the job, pretty sure boofhead is/was still running the stock pump on his a12 with twin 40mm webbers

need to check fuel pressure
and blow out fuel lines or replace

It could be your jetting, a little on the big side? Does the engine start to make the droning sound as you try to accelerate hard and then begin spluttering ('dut, dut dut, dut' engine sound)?

Sometimes as you accelerate under load (especially in the higher gears) it'll start to hate it (richen right up) and begin spluttering, sometime you have to clutch in and rev it to burn the excess and then it goes okay again until it over fuels itself again.

Me and Gylezy have this issue with our carbs fueling on main circuit when under load in high gears and low to moderate revs.

Never heard of the stock pumps running out of wind (except in race applications and different fuels) unless, like you said fuel lines or facet diaphragm or spring have failed. Otherwise jam an exhaust gas reader up the exhaust and see what it's doing?

its a little flat up top( bit rich 145s could be 135s)
also could be cam
it pulls realy well
no noises,just sweet induction,need to tune acc pump(stuter just)
7000 1st 7000 2nd 5000 3rd out of fuel,starts to die
back off fill the bowls and away u go again
with std jets it runs realy well allmost good enough not to touch
idles realy nice tune screw out 5.5 turns a bit high 1000rpm idle
but cant get any lower(butterflys need to be losend and reset i think)
but very happy just need to keep fuel up to them
ps: gone from $10 a week fuel to $45 from when fitted 9 days ago

Why don't we keep it simple & go with the usual suspects first.

Replace the fuel filter[s] first.
A partially blocked filter will allow a restricted fuel flow giving normal performance at low throttle settings, but restricting the flow enough that the carb runs out of fuel at high power/high fuel useage settings.

Filters are cheap & easy to replace & are responsible for this type of condition in the VAST majority of cases.
Don't forget to check any gauze strainers that mat be located inside the carb, usually just before the needle & seat.

If symptoms persist, then go to the next step.

i have an electric fuel pump on my a14 with twin webber 45's and dont have a problem the standard pump was good but i just wanted the extra fuel for when im reving it out... but idling in heavy traffic it starts to flood big time..

could you use a bigger fuel filter that holds more fuel? i did it in the sedan with the twin sus for a little while- held almost 1/3 more fuel- should be enough head room to get you through the flat spot.