Weird, sudden AFR issue Proform 750cfm!

Fuel and Air Systems

  1. MOPAROFFICIAL

    MOPAROFFICIAL Well-Known Member

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    Okay. You did or didn't lose the check ball, but you maybe didn't have the gasket back in under the shooter eh?
    2, one under shooter, one above under screw head. If its leaking.. one or both are bad and no amount of tightening will stop a leak. Lesson learned. Sucks.
     
  2. mopowers

    mopowers Well-Known Member

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    You can repair it with a helicoil and use the squirter screw with the hole down the middle. I believe it's a 12-28 thread.
     
  3. KnuckleDuster

    KnuckleDuster Well-Known Member

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    I had new gaskets. They are the thin metal washer type. It was still leaking from just snug, right up until the threads broke.
    What is the secret to getting the squirters to seal?

    Anybody know a good source for the hollow screws that don't cost $10-15 each?

    I have another used carb I bought that I haven't had time to mess with yet, but I do know both the squirters were leaking. Don't know why that didn't clue me in this could be the problem with the carb on the car!

    Looks like the threads stripping on these is a pretty common issue. Maybe because of the slots? ...and aluminum. Seems like a bad design in combination with metal gaskets.
    I bet the other carb has the same problem, so I want to buy 4 hollow screws and do them all.
    The heli-coil kit is already $40, but has 15 inserts.
     
    Last edited: Apr 27, 2019
  4. 12many

    12many Well-Known Member

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    The AED I have has nylon type sealing washers for the squirters, as well as for the bowl/block screws. There are thin and some are much thicker but I've used that style for many sealing bolts/plugs etc on all sorts of applications and never had leaks. If they are thicker the thread (fine especially) engagement might be reduced, but if the threads are repaired they are what I'd use. I just sneek up on the final tightening, a slight snug beyond seating. Never worry about stripping things.
     
  5. yellow rose

    yellow rose Doctor of Thinkology.

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    As 12many said the nylon gaskets are much better than anything else. Even the paper gaskets.

    I only use the Superformance gaskets on carbs any more. For about 40 bucks shipped you can get his kit with all the gaskets in it, although now that I've typed it out...I'm not sure it has nylon squirter gaskets in it. Damn.

    In that case, you can go to any GOOD hardware store and they should have some thin nylon gaskets for cheep in their bulk section.

    I still suggest the Superformance gasket kit because they are the best I've found, but I don think it has squirter gaskets in it. I may call him and make that suggestion. Greg is a great guy. Who knows...he may add them to the kit if someone asks.
     
  6. mopowers

    mopowers Well-Known Member

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    If you need the helicoil kit, I've got one I can toss in the mail for you to borrow. I bought the "Recoil" brand kit a few years ago to do mine and only used one of the 15 inserts, so it's got plenty of inserts left. You're welcome to use it if you send it back. Send me a PM with your address if you want to go that route. I even have an extra hollow squirter screw and some paper gaskets I can include free of charge. I've had good luck with paper gaskets on the bottom and the metal ones between the screw head and nozzle.
     
  7. KnuckleDuster

    KnuckleDuster Well-Known Member

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    WOW! THAT IS COOL OF YOU!
     
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    • KnuckleDuster

      KnuckleDuster Well-Known Member

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      I will look into it, I still have that other carb to go through, also. I talked to him on the phone when I was looking for a rear main seal. Hell of a nice guy!
       
    • KnuckleDuster

      KnuckleDuster Well-Known Member

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      Oooook...helicoil is done. Everything is back together. Three gaskets and a different shooter later....same problem!
      Fuel dribbling out of or out from under shooter, cant even tell anymore, I can only see it dribbling down the carb body behind the primary shooter. Also the shot from the squirter seems weak and sloppy, with both a 31 and a 35. ( smallest I have on hand)
      Accelerator pump? Diaphragm or check valve?... or both?

      Could taking the carb apart so many times cause this?
      Ethanol?
      WTF???
      Really at my wits end.
       
      Last edited: May 3, 2019
    • mopowers

      mopowers Well-Known Member

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      Maybe get a magnifying glass and look for a crack? What part # is the carb?
       
    • KnuckleDuster

      KnuckleDuster Well-Known Member

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      This one.

      20181030_175304-1.jpg
       
    • KnuckleDuster

      KnuckleDuster Well-Known Member

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      Changed accelerator pump and check valve. No dice.
       
    • mderoy340

      mderoy340 Well-Known Member

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      Don't crank on the screw so much or it strips the threads. I make my own gasket out of thin paper and throw the metal ones in the trash.
       
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      • 12many

        12many Well-Known Member

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        Do you have the thin coated crush sealing washer/gasket installed "between" the screw and shooter, along with the gasket that goes between the shooter and body?
         
      • KnuckleDuster

        KnuckleDuster Well-Known Member

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        Yep. Tried a fiber gasket on the bottom that Mopowers sent me. I bought some Demon 190017 gaskets, gonna try those next. I have to walk away for now. Too pissed, and now it's storming, so I can't test drive any more today.
         
      • crackedback

        crackedback FABO Gold Member FABO Gold Member

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        What do I win? :)

        Is the check needle under the squirter? Didn't read the entire thread. Sometimes there is enough signal to pull fuel up and out the nozzles even if the needle is there.
        holley acc pump needle check - Bing
         
      • KnuckleDuster

        KnuckleDuster Well-Known Member

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        Yes. It's been there the whole time.
        I did look for a crack, and couldn't find one.

        Rebuilt my other Proform this morning. I wanted to, anyway. About to go swap it out in a bit, took a break to go see a car show.

        Tony Defeo suggested checking distributor advance to see if it's hanging up, or maybe a weak coil, since I've been through the carb so many times already.
        So, if the other carb does the same, I guess that will be next.

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        • crackedback

          crackedback FABO Gold Member FABO Gold Member

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          Are you positive it's leaking from the squirter base?

          Maybe try this. Get the car warmed up so it will run without having to hit the pedal. If it does need some prime, use the other pump. Dry the area with cleaner or air. Fashion up a piece of paper to block any air flow past the squirter or tape over the nozzle openings to rule out siphoning. Fire it up and see if it still leaks. Not sure I would dust the area with a powder to show leak pattern. Desenex on oil leak sources is great!
           
        • KnuckleDuster

          KnuckleDuster Well-Known Member

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          Well the new carb does fine. Whether the squirter is siphoning, or just not sealing, or the carb is leaking somewhere else, I don't care anymore right now. After this ordeal, I don't want to see it for a while. Maybe I'll go at it again later, or maybe it will be parts for a future 850-950 build.

          This new one is an older Proform race 750 model. Gonna have some fun playing with it for a while. It's a pretty nice piece that just needed a little love and a kit. I really do appreciate all the help and tuning advice. Don't worry, it was not wasted. As frustrating as this was, it was great experience, and it really got me interested in learning more about, and doing more with Holley carbs.
           
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