Jump to content

Spitfire SU Carbs


Recommended Posts

Finished building the car last year and ran it around last summer. This March had the carbs tuned and ran fine. Now the rear carb keeps overflowing, so bought new float and jet etc but still overflows after about 20 seconds. Adjusted the float as per the manual but still floods. Had the front float out and all looks ok. What next to stop it flooding?

Link to comment
Share on other sites

Have you got a new pump or the original ? most new ones put out too much pressure, up to 6psi when you only need about 1.5 -2 for SU`s.

I believe you can use spacers on the pump mount to relieve the arm a bit giving lower pressure.

If you have new floats and Jets (do you mean float valves?)  try removing the float lid and closing the valve with your finger and see if you can blow air through it, if not it must be too much fuel pressure.


Link to comment
Share on other sites

I had the same problem with the front SU HS6 on my Sixfire. Initially, I padded out the pump with extra gasket adding about 3mm of spacing. Ultimately it was Pete Lewis's favourite "black slivers" of rubber that was causing the problem. Changing all of the fuel line rubber for Gates Barricade (available from the club shop and other sources) resolved the problem completely and the extra gasket is now removed. Since then, I have switched to a pair of Stromberg 150s and back to the SUs for comparison. The Strombergs are superior in every respect!

Edited by Stratton Jimmer
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...