My 1978 MGb has been fitted with dual Su carbs I just replace the Su fuel pump and now when warm it idles way to high. I have adjusted the idle control all the way down. I can’t seem to find any lean/rich mixtures on the carbs. Any ideas?
Sounds like you have a vacuum leak or your carb.linkage is out of adjustment. Loosen the linkage clamps including the ones for the choke and see if the idle drops. Are the carbs HS-4 or HIF-4?
Are you trying to find out how to make the mixture leaner or richer? What model of SU Carb are they, that would be helpful. As mentioned, loosen any connections to accelerator or choke and see if that helps. Carbs should be disconnected from each other to balance them, that means loosening the clamps that hold the throttle shafts together. Let us know what you find out.
