'74 Duster - stalls easily

Mopar Performance Issues

  1. Max_118

    Max_118 Active Member

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    Hello! I have a '74 Duster with a 318, 2 barrel carb. A very solid car, no rust, and less than 100,000 miles on it. It will start easily, and idle fine after it warms up. However, if I take it for a drive (just around the block so far) it will stall when I let off the gas. I made 100% sure the engine was at it's normal operating temp while doing this. I'm using fresh gas. (I don't know too much about cars, but I suspect this may be a carburetor issue.) I plan on giving it a tune up to see if that helps, but in the meantime if someone has some pro tips, I'd appreciate it.

    Thanks!
    - Dave
     
  2. 70dart340

    70dart340 Well-Known Member

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    Is the idle RPM correct? You said you're new to cars, so I'm just trying to help with the basics. I'm not insulting you. Paul.
     
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    • Max_118

      Max_118 Active Member

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      No insult taken! I'm here to learn and get other people's thoughts, so it's all good.

      I adjusted the carb idle (my ignorance is showing here - I turned the little flathead screw on the carb) until the idle was slightly higher than normal. I know by the sound about what the idle should be. This was before I tried driving it, so the issue was still there.
       
    • 70dart340

      70dart340 Well-Known Member

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      If you have a buddy with a timing light, you can make sure the idle isn't too low.
       
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      • Bewy

        Bewy Well-Known Member

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        Make sure the choke blade is vertical at operating temp, & not flopping around. flopping around indicates a failure of the choke system.
         
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        • Tooljunkie

          Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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          Usually i find a dirty carb can cause this issue. Idle circuits restricted. Adjusing idle mixture screws are the telltale when there is no change when adjusting for a better idle.
           
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          • 67Dart273

            67Dart273 FABO Gold Member FABO Gold Member

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            If you never have, I would just do a through and complete tuneup

            1...Do a compression test and leakdown test. I don't remember if the 74's have adjustable valves if so check them
            2...Examine all ignition components condition, wires, cap, rotor, etc, and set timing. Don't set it to "stock" which is likely TDC. Set it for at least 5BTC
            3...I agree that the idle problem is likely a carb "getting" (gotten) dirty. You might get lucky. Sometimes you can pull the idle screw, blow some cleaner through it, then reset. Pull it again idling, work the throttle and hold your finger over the screw hole. This will suck air through and also help clean it

            Set timing BEFORE you adjust carb. Set carb fully warmed. Make CERTAIN you have not lost track of any vacuum hoses and let them open. Adjust mixture for highest vacuum or idle speed, and "finish" with screw "just leaning" towards lean (CW) side. Reajust idle speed and mixture at last
             
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            • CRUZE 418

              CRUZE 418 FABO Gold Member FABO Gold Member

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              Orginal engine? That engine has a nylon tipped teeth on the top timing gear, they can start to fall apart at around 100,000 mi. Heat crossover is starting coke up with carbon. Flat lobes on camshaft, heads need hardened seats. This is most probably not your problem, but be aware that all of these things will start to add up. Tearing down my '72 318 right now and besides hemorrhaging oil, have found all of this, and it ran fine.
               
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