Sourcing 5-6 psi fuel pump help

[ahoke]

Fuel pump went out on my '72 C20 350 with the stock quadrajet. The one that was on it was a AC Delco mechanical pump with a 3/8 outlet fitting and a return line with the elongated pump body. Took a while but I found this one from summit:

https://www.summitracing.com/parts/CRT-M6101

Installed and the carb is flooding, rebuilt the carb, adjusted float, still floods. Looked on carter's website and says the psi min is 7.5 and max 9, not the 6 summit states. ANYWAY.....anyone have any advice on finding one with lower pressure rating? From what I can tell quadrajet likes about 5 or 6psi. I'd prefer not to have to add a pressure regulator inline if I can avoid it.

[53burb]

I haven't heard about quadrajets being sensitive to pressure....Edelbrocks I hear alot of....one of the cures they use, if they dont want to use a separate fuel regulator, is they use an Edelbrock fuel pump...they pump at a lower psi....

[Rust_never_sleeps]

Is there fuel flowing back to the tank through the return?

[jumpsoffrock]

I don't have particularly good news for you, but this issue is not anything new and is all over the internet.

The short of it is that the fix is to start running a pressure regulator.

I run a stock Holley 1-bl carb on my old ford truck for 10 years with no regulator--thousands of miles between 2011 and 2021. Pump installed in 2013 or so went bad and replaced with a new one, and for heavens sake I couldn't get the bowl to stop overflowing.

I paid $50 at autozone and got a simple regulator. Generally speaking it fixed my issue.


The talk on the internet is that the pressure regulation of most new pumps is very loose, with most pumps putting out 8-9, and some youtube people saying they've seen 11-15 from a stock mechanical pump meant for an application that calls for 3-5 psi. Not ideal....


Good luck.

[54blackhornet]

I had the DualJet rebuilt for my 71 C/20 307. It would not run properly until I installed a fuel regulator. I had an inexpensive Mr Gasket on my shelf, installed it and set it for five lbs. engine runs like a sewing machine now.

[1970cstblazer]

Originally Posted by ahoke

Fuel pump went out on my '72 C20 350 with the stock quadrajet. The one that was on it was a AC Delco mechanical pump with a 3/8 outlet fitting and a return line with the elongated pump body. Took a while but I found this one from summit:

https://www.summitracing.com/parts/CRT-M6101

Installed and the carb is flooding, rebuilt the carb, adjusted float, still floods. Looked on carter's website and says the psi min is 7.5 and max 9, not the 6 summit states. ANYWAY.....anyone have any advice on finding one with lower pressure rating? From what I can tell quadrajet likes about 5 or 6psi. I'd prefer not to have to add a pressure regulator inline if I can avoid it.

I hate Carter mechanical pumps. Never had any luck with them. I would get at minimum a Delphi brand or AC Delco brand replacement pump. I'm running a reman 1990 vintage AC pump on my Blazer. I don't use any fuel with ethanol in it, so it works well.

[twoskies]

Had a Rochester on mine from the Start, kept having issues with it, Carb not fuel pressure, pressure with Stock Fuel Pump was always 8 to 9
Bought an Edelbrock and hooked up Pressure Regulator
Not had an issue since

Besides, the Regulator looks Custom. lol

But i already bought an Edelbrock Fuel pump 6 PSI max, going to change it out this Winter, probably still run the regulator