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Thread: Pressure Regulator Question

  1. #11


    Those regulators are crap. Throw it away and get a better one. Been there, done that!

  2. #12


    Over three years old, but I'm interested in hearing whether or not the problem was solved. What I see is a return style regulator and AFAIK, the part that came with a Mallory Regulator, to install in the fuel pump, replacing the bypass spring, seems to be an illusive, almost phantom part, that no one from MSD, Summit, Holley, Amazon, O'Reilly, AutoZone, Advance, etc., can seem to locate. It was kinda dumb, but you don't need the spacer if you're not using a return style regulator, so they shipped the spacers with the return style regulators. Except they forgot to include one in mine, the 4307M (MSD-29259), because for whatever reason, they lost their initiative when it came to marine parts.

    I have the same problem, which is basically the Fuel pump and regulator confusing the crap out of each other and in my case, the fuel bowl is pumped dry. I ain't rich, so I ain't tossing a good, fairly new fuel pump or regulator aside, just so I can purchase more parts, which have to have 3/8" NPT ports and be alcohol approved. I'll post a new thread later with my inquiry, I was just wondering, as stated in the beginning, and although late, offering up my knowledge regarding the illusive "spacer".
    Click image for larger version. 

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  3. #13
    Join Date
    Jan 2010
    Brisbane, Australia


    I've never run the spacer, can't see any need, and can't see why you'd want to run the pump in this manner, totally unnecessary.
    Bypass regulators run fine when set at pressures suitable for carbs. The regulator in the fuel pump is set way higher than a carb will ever need.
    Don't ever blame a regulated pump and a bypass regulator as a cause for lack of supply. Look at your WHOLE fuel line, including the pickup. Gary
    Regards, Gary

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