Twin 40's confusion
 

I have a Mk3 escort which im in the process of putting twin dellorto 40 carbs on.
I removed the mechanical fuel pump and blanked it off, fitted the carbs, baught a fuel pressure regulator and a facet solid state fuel pump. Ive started to plumb it all in but i am confused that the dellortos dont seem to have a fuel return?
If these carbs dont use a fuel return, how does the fuel pump know when to stop pumping fuel into them??
Does the facet fuel pump simply 'cut out' when a certain amount of pressure builds up in the fuel lines??
The instructions for the pump say it needs to be connected to the oil pressure switch, is that neccesary??
All help gratefully recieved, as ive realised i dont know half as much as i thaught i did about these things!! :? Lol!

street

the pump pumps continuously and the carbs have floats in them that cut the incoming fuel when they reach the top (bit like the ball cock valve thingy in your loo) when the carbs are full and dont need any more fuel the pump just dead heads (pumps nowhere but its only low pressure)however when the cars running you dont get that situation because there is a constant small use of fuel and therefore a constant small replenishment, the reason that its recomended that you connect up to the oil pressure switch is because if (god forbid) you had an accident and the fuel lines split and you where unable to turn the pump off, the fact that the engine would stall and therefore have no oil pressure and therefore cut the pump out and stop it pumping fuel everywhere. basicly its a safety feature and its your choice personally i would do it. is that all clear? if not ill try harder next time :top: :top: :top: :top: :top:

Ah i see! But when you say the pump deadheads, just pumping the fuel nowhere, does that mean there IS a fuel return pipe from the carbs back to the tank?
If so where the hell is it on dellortos?? :?

street

no theres no fuel return the pump just carries on pumping but moves no fuel because theres nowhere for it to go and unlike an injection system because its low pressure this doesnt matter. and therefore you dont need a return

Oh okay! Thanks for ya help there trev! :top: :top: :top: :top:

street