My turn to ask for help with a Holley.

Discussion in 'Fuel and Air Systems' started by TrailBeast, May 17, 2018.

  1. TrailBeast

    TrailBeast Slightly Twisted Member

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    UPDATE
    Got er done except for the missing bowl gasket, secondary accelerator pump diaphram and accelerator pump diaphram check valve.
    All missing from a new verified correct unopened Mr. Gasket kit.
    :BangHead::bs_flag:





    A friend is fairly busy and has two carbs that are acting up and he asked if I could help.
    The one in question is a Holley 9379 750 double pumper competition carb with four corner idle jets.

    It's been forever since I rebuilt a Holley, and I thought I would ask if there are any special things to look out for.

    Thank you.
     
    Last edited: May 18, 2018
  2. fklskv

    fklskv Well-Known Member

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    Verify the power valve is proper for your vacuum first.

    Idle screw are like a faucet in cuts the gas, out increases. The must be the same.

    That should get ya started.
     
  3. 67Dart273

    67Dart273 Well-Known Member

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    Been many years, I used to "kit" many many Holleys for friends when I was in the Navy and after. My big problems with 'em were leaking power valves----sometimes right out of the box, and sometimes creeping float levels. I only remember one that I "figured" had a cracked main body, that was on a little 4150 likely a 650 vacuum
     
  4. jbc426

    jbc426 Well-Known Member

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    Be sure to get the newer non-stick gaskets. Watch a lot of the on-line videos about rebuilding, adjusting and tuning Holley carbs.

    Pay close attention to the position of the throttle blades in relation to the idle transfer slots.

    Install a wideband A/F gauge to help tune the air/fuel ratios across the board.
     
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    • TrailBeast

      TrailBeast Slightly Twisted Member

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      Ok ,thanks.
      I looked up all the adjustments and settings on the Holley website as a refresher, and the kit has the blue waxy feeling gaskets. (non stick I think?)
      It's not my carb and the guy isn't going to buy an A/F gauge.
      I guess most of the carb/Holley guys are on vacation:D, but thank you for your info.
       
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      • fklskv

        fklskv Well-Known Member

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        If you posted some symptoms we could dig up more info. If he has two carbs acting up, that sounds like something other then the carb.
         
      • pishta

        pishta I know I'm right....

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        No you got it. Non stick gaskets, maybe a flat plate and some fine sandpaper to check
        flatness of metering blocks, also a wire guage pipe cleaner to run through the finer orifices and some compressed air to blow out carb cleaner. Wear glasses when you do that as you never know where it's going to come out. Also don't disturb the plates on the shaft. An un-needed step and hard to get them centered again.
         
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        • yellow rose

          yellow rose Doctor of Thinkology.

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          Superformance gaskets are far and away the best.

          Make sure the main body is flat. If it's billet it probably is. If it's cast, it probably isn't.

          Also, screw the power valve into the metering block and put the metering block on the main body and make damn sure the power valve isn't hitting the boss in the main body. 90% of the cast main bodies hit the power valve, especially with the tick power valve gaskets they use now. I've only seen one billet main body have that issue but I check them all.

          Also, set your power valve opening based on cruise vacuum and NOT on idle vacuum.
           
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          • KitCarlson

            KitCarlson Well-Known Member

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            If it has nirophyl floats, they can fuel log. After dried out they can work for a few days... Replace with brass if available,
             
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            • TrailBeast

              TrailBeast Slightly Twisted Member

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              The Holley has sat for quite awhile so he wants it gone through.
              That one is going back on a built big block 440.

              The Edelbrock 1405 with electric choke kit he just rebuilt but it drips from the boosters no matter how he adjusted the floats.
              I'll be looking over the brass floats for leaks and the needle and seat really well.
              Also be testing that one with fuel pressure and make sure all the gaskets are right.
              I asked if he made sure he put the accelerator pump check ball and weight back in and he described it in detail.

              Thanks for taking the time to give your thoughts on it.
               
            • Mattax

              Mattax Just the facts, ma'am FABO Gold Member

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              The blue gaskets are fine. If planning to do any tuning, kill the sticky with a little wd-40.
              This is just a rebuild and go?
              Check the o-rings on the fuel inlet nead and seats.
              Do not use nylon gaskets on the fuel inlet fittings. Use hard fibre or Holley metal ones.

              Either of Mike Urich's books covering 4150/60 carbs has good step by step with pictures.

              Set the primary throttles so they are shut. Count how many turns in are required to show .020" of the transfer slot, and then .040" write those down. That's the working range. Adjust intial timing, PCV air, etc as needed to adjust idle rather than going outside of that range.

              Really the main thing is cleaning out the varnish from old fuel and replacing any deteriorated seals and gaskets. The older parts weren't always made to withstand some of the stuff that's put in fuel since they were made. That's one therory about the rash of power valve failures in the early to mid '70s.
               
              Last edited: May 18, 2018
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              • JoeSBP

                JoeSBP RLTW!

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                Lots of good videos on YouTube.

                Also on the gaskets, I always just give them an ultra thin touch of plain chapstick. No mess, and no stick/tears later
                 
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