I have two A's with Weber 32/36 carbs. Both cars are using the Holley low pressure regulators. The Zipper is running 4 PSI and the CCPU is 2-1/2 PSI. Correct pressure should be no more that 3 PSI Cannot adjust the Zipper to less than 4 PSI. Question is, do I replace the regulator and/or the gauge? As always, thanks in advance for your input.
May just need to replace the diaphram in the regulator, they will get stiff with age. Holley sells a rebuild kit, but IIRC the diaphram is just the same as a 30cc accelerator pump diaphram
So...it sounds like your zippers stuck. New Holley 12-804 is 35 bones from Summit. They claim adjustability from 1 to 4 PSI. There are other Holley regs that look like the 12-804 but cannot be turned down lower than 4 PSI. Like the Holley 12-803 which adjusts from 9-4.5 PSI. Visually identical. Do you know for sure which one you have in the Zipper?
Holley regulator kits have 2 springs included, High and low pressure. https://www.summitracing.com/parts/...MImK6is8ue7AIVVgiICR3Uhg1-EAQYASABEgIqe_D_BwE
Are you sure its a real Holley? There were a bunch of counterfeit ones a while back but I don't know if Holley was one of the brands that was being ripped off.