Fuel Chamber Overflowing

[TurboTux]

Evening all,

So I've rebuilt my SU HS2 carbs on my Mk1 Spitfire as well as replacing the mechanical fuel pump and fuel lines but when I've come to set up the carbs, the float chambers are overflowing. The rebuild included new jets, needles, fuel float needles + seats and new floats.

I've tried to adjust the float level multiple times, cleaned the seats and needles and nothing I do cures the problem. I'm starting to believe the new pump is causing the line pressure to overcome the floats so I'm thinking of getting a fuel pressure regulator but I feel like thios shouldn't be necassary 😐

Any tips or ideas would be appreciated.

 

Tux

[Steve P]

A lot of the modern repro pumps put out way too much pressure for SU`s,i think from memory 2 psi is fine.

Had experience of this when i put a new pump on my 1500 Herald.I went electric in the end.

Steve

[DanMi]

if you still have the original fuel pump get a rebuild kit and refurb that. Often better these days to refurb original parts than my modern repro

[Pete Lewis]

swap the spring from the old pump into the new pump  its the spring which determines the output pressure 

or cut a bit off the new pump spring 

 far cheaper than buying  a regulator 

Pete