Another 318 carb issue!!!

Discussion in 'Mopar Performance Issues' started by tsa_035, Apr 15, 2018.

  1. tsa_035

    tsa_035 72 Plymouth Duster

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    Hello friends!!!!

    Long story short, 72 Duster 318, Eddy performer cam (.420 lift), Performer intake, Eddy 600 CFM, mechanical choke, headers, and pretty much stock motor. Less than 5K on the rebuilt 904, 8 3/4 with 3.55 gears. Sat for a few years, drained the gas, plugs and wires. Starts up ok, but it is like pulling teeth to go over 60 MPH. She sputters and sounds like she is missing real bad.

    What I have done so far - rechecked all the wiring to the plugs, checked timing, air fuel ratio, timing again, air fuel again... When she is running the idle is smooth bt 700-800 RPM. Under any load she lags and sounds crap. Any ideas???

    Thank you ahead of time,

    Danno
     
  2. krazykuda

    krazykuda FABO Gold Member FABO Gold Member Technical Editor

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    I would look close at the carb for issues....

    It's probably a little gummed up from sitting...
     
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    • Tooljunkie

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

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      I agree,carb gummed up. May need an overhaul.
       
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      • tsa_035

        tsa_035 72 Plymouth Duster

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        Thank you both for the suggestions!!! I for sure will go through the carb!!! I will do a follow up and let you know how it did
         
      • tsa_035

        tsa_035 72 Plymouth Duster

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        Rebuilt the carb works great... Now working out some electrical short some where in the system.
         
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        • Mopar Tim

          Mopar Tim FABO Gold Member FABO Gold Member

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          Well a short finds itself, it burns up! Good luck.....
           
        • tsa_035

          tsa_035 72 Plymouth Duster

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          Ok, now another issue... Back at the carb again... I am leaning towards vacuum. It has the Edelbrock Performer .420 lift @ 204* duration. I cannot get this dang thing to idle!!! A list of check off and what I have done.

          Reset the fuel mixture screws to about 1.5 turns. With the idle screw barely touching the plate on the carb (Edelbrock 1405) it idled at about 1800 RPMS. It would fluctuate from 2600 to 1200 RPMS. Plugged the carb for vacuum advance and checked timing (obviously idling way to high to check). Retarded it to bring the RPMS down. Got it to idle about 1200 RPMS (Fluctuate between 600 to 1800). At this point the idle screw is completely not even touching the plate.

          Thinking I have a vacuum leak, I sprayed carb cleaner around the base of carb. Could'nt tell if fluctuation was from the spray or the fluctuation of idle. On side of caution I replaced the adapter plate and placed a half inch spacer on the intake. Still have a fluctuation of idle between 900 to 2000. When in any gear it drops to about 400 to 600. Sprayed carb cleaner around carb base and nothing. When it idles about 900 and give any throttle, the motor reaches about 2200 to 2500 and stays there for about five to ten seconds. Shaking my head.

          I am leaning towards a meter. Not 100% if it is vacuum related or not.

          On a humor side, My neighbor came over when I was working on it and said oh man sounds good. Sounds like you got a big cam in there. All I could do was laugh and think to myself she is supposed to idle smooth.
           
        • krazykuda

          krazykuda FABO Gold Member FABO Gold Member Technical Editor

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          I like to use this carb base gasket:

          Edelbrock Heat Insulator Gasket

          First get the timing dialed in... Start around 10° - 15° advance and see how it runs...

          then dial in the carb next...

          That cam should idle at 700 - 800 RPM ... Something is not right...

          Also check to make sure that you haven't mixed the #5 and #7 wires on the distributor...
           
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          • tsa_035

            tsa_035 72 Plymouth Duster

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            Totally forgot to tell y'all. I triple checked the wires to ensure that. My issue is I can't set the timing with the rough idle. When I retard the timing it dies out on me. The timing then bounce around when the RPM's start fluctuating (Even with the vacuum line is disconnected from distributor and plugged on carb).