Slant 6 hesitation or stumble

Mopar General Discussions

  1. dazedand confused

    dazedand confused Well-Known Member

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    I have a 1965 dodge dart with a slant 225 slant 6 with a Carter 1barrel carb and points distributor . The during warming up and after fully warmed up has a good even idle with no miss. When i go to give it gas it stumbles/hesitates then picks up? I've checked the timing,points and points gap and fuel pressure.i use fresh 91 octane no ethanol. I took my time and fully rebuilt the carb including cleaning out all ports and passage ways and no fuel leaks or vaccum leaks ? The only thing i can think of is the vaccum advance or it could be out of adjustment from being on the car for many miles even thought i bought it remanufactured from O'reallys . What's your guys thoughts? Thanks
     
  2. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    Hot idle may be too lean.
    Is the timing and idle speed set to factory specs for '65 ?

    Since its not happening cold, sounds like choke is covering the problem.

    But if you suspect the vacuum advance, leave it plugged. (golf tee in the hose just like when setting timing)
     
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    • moparmat2000

      moparmat2000 FABO Gold Member FABO Gold Member

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      Check to make sure your mechanical advance weights arent sticking.
       
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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      It's missin two cylinders. Get used to it.
       
    • kesteb

      kesteb Well-Known Member

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      So you bought a new distributor from O'Reilys? Who knows how it is setup. They are usually assenbled from a mismash of parts. Do you have a dial back timing light? If you do, then you need to map the advance. If not, I would try advancing the timing 5* and see how it runs.
       
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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      Not true if it's a NEW one as the only new ones they sell are from Spectra. That's the same Spectra that makes fuel tanks, sending units and "all that" and they're located in Canada and make all their parts right here in North 'Merica. Now, that said, before I left O'Reilly, All they had available were two A1 Cardone part numbers. One without the cap and rotor and the Cardone select with the cap and rotor. Both those numbers were reman units, not new. BUT, only one, the one without the cap and rotor was available, although both were in the system. I left on Easter Sunday, so, maybe the new Spectra units are available now, but "I doubt it". I fully agree though, any reman unit from any of these parts stores should be set up accordingly, as they are just slapped together. Plus any electronics they have are total crappola.
       
    • pishta

      pishta I know I'm right....

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      make sure the advance plate in the distributor advances cleanly pulling a vacuum on the line with a source and snaps back when its released. Also check your choke pull off if a carter has one. At full warm, your choke should be straight up and down. If not, find out how to adjust it so. I only worked with Holley 1920's.
       
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      • dahdgedaht

        dahdgedaht 1971 Swinger Special 340 TRIBUTE

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        Vaccum leak? I had a few slants that would stumble off idle. You would need to feather the gas a bit to get it to accelerate smoothly. Narrowed it down to a possible intake leak and/or throttle shaft leak. Look for wet spots on the carb near the throttle shaft.
         
      • dazedand confused

        dazedand confused Well-Known Member

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        It has a manual choke .it does the stumble cold or hot when you go to give it gas couple seconds and if you stay on the gas it picks back up? Idles great
         
      • dazedand confused

        dazedand confused Well-Known Member

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        ??? Get use to it? Pistons and valves and head are all in good shape not burning oil head was shaved 0.050's all new plugs good spark good coil ?
         
      • dazedand confused

        dazedand confused Well-Known Member

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        i've checked for leaks . Sprayed around gasket base of intake and carb . No fuel leaks either sprayed around carb nothing?
         
      • dazedand confused

        dazedand confused Well-Known Member

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        I've checked and adjusted the timing no changes?
         
      • Mattax

        Mattax Just the facts, ma'am FABO Gold Member

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        That changes things a bit.
        What do you mean by give it gas? Gently easing it? hitting it quick? In gear? out of gear?
        Idles great? Do you mean in Drive or neutral? What rpm? Do you have a vac gage? a CO meter? Some guys can hear and smell the differences but that takes experience.

        He's joking.

        Red herring

        I agree. That's not right.
        Tell what you did, and what you measured.
         
      • dazedand confused

        dazedand confused Well-Known Member

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        ok so at idle in park or in gear it idles great . When i go to press down on the pedal: gas it stumbles for a quick second or two then picks back up? I've checked everything to specs : factory ect . except for the counter weights sticking and or vaccum advance not working or needing adjusted a little. I believe the vaccum advance works because it starts right up with no hesitation or cranking needed? But under load vaccum advance might a little bit out of adjustment?A little while back i made sure the gap between the rocker arms and valves where properly adjusted running while at full warmed up temps.
         
        Last edited: Aug 14, 2019 at 1:11 PM
      • DodgeLad

        DodgeLad Unicorns -> rainbows -> lollipops

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        Last resort stuff....on the carb, maybe a leak where the throttle rod (the part the throttle plate attaches to) goes through the bushings. Slop there results in a vacuum leak. Or an intake manifold leak.

        I had a very similar problem, NOS Holley carb, Remflex manifold gasket, and discoed the emissions stuff. Problem gone.
         
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