Rebuilt carb can't idle - 68 Cuda

Discussion in 'Fuel and Air Systems' started by Traxfish, Jun 30, 2018.

  1. Traxfish

    Traxfish Active Member

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    Today I got done cleaning out the stock 318 carb and replacing the gaskets with a rebuild kit. Put things back together and the engine will turn over but immediately die. If I feather the throttle it'll hold about 1200 rpm and sound fine. I've been messing with the idle mixture screws without any noticible difference. Any other ideas on what's gone wrong?
     
  2. Dana67Dart

    Dana67Dart Most undignified way to get to Colorado!

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    2bbl 4bbl???

    Which carb BBD AFB etc.

    Why did you rebuild the carb, what condition prompted it?

    Float valve set to correct level?

    Vacuum ports connected correctly and or plugged correctly?
     
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    • Traxfish

      Traxfish Active Member

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      More info would be good yes. I am not super experienced with Carbs but decided to take a crack at it with the service manual and the diagrams that came with the kit. This is the kit I used: Carter BBD Carburetor Kit Chrysler, Dodge, Desoto K4072

      It's the Carter BBD 1-1/4. It looks like the solid fuel design.

      I rebuilt it because it the vehicle started hesitating pretty badly. It had been sitting for a couple years in the previous owner's care and when I changed the fuel filter a lot of mud-like fine particulate came out of it. Sure enough, the bowl of the carb with filled with the particles too.

      It was also smoking out of the carb after trying to run it. I realized that could be a sign of something as well.

      I am trying to find the float valve in my diagram and can't find it. Could it be listed as the float needle that's in front of the carb at the fuel intake?

      Vacuum hoses went back on as it was before I started messing with things.

      Reading further float adjustment could be the culprit.
       
      Last edited: Jun 30, 2018
    • Dana67Dart

      Dana67Dart Most undignified way to get to Colorado!

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      If the float is too low / high (depending on your perspective) the needle will not allow fuel into the carb fuel bowl until the fuel in the bowl is too low. In a nut shell there are passages in the carb that siphon fuel from the fuel bowl at idle. if the fuel is below that port level no fuel will get into the engine. at a higher RPM different ports are in play and they might be in fuel the entire time.

      Keep plugging at it.

      only other idea at this time is a plugged passage after carb cleaning. the fine sludge could have gotten into some of the small ports. if all else fails pull it apart and blow air through every port and hole you can find.

      Oh one other thing many kits have multiple gaskets perhaps you used the wrong one and blocked a passage, or put in on upside down and blocked a passage. I have a few dozen photos of my 2bbl carb rebuild including tear down if you want I can e-mail them to you. PM me if you want.
       
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