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Carb Question On 304

Discussion in 'Intermediate CJ-5 and CJ-6 Tech' started by B-Rad, Jul 5, 2018.

  1. Jul 5, 2018
    B-Rad

    B-Rad New Member

    Dayton
    Joined:
    Jun 14, 2017
    Messages:
    42
    Hey evereyone, Hope your all staying cool. I let my Jeep sit for about a month. The motor has maybe 600 miles on a rebuild. Running good since the first start up. The carb was professionally rebuilt, a holley 4 barrel believe its a 600 or 650, jetted pretty small. Was running good before I let it sit.

    Drives good on the way to wherever, let it sit either 8 hours or just eat lunch and then the Jeep goes real lean on Decel, almost stalls the motor, but one you actually stop, it idles back up and is fine.

    Any clues? I check all the plugs and they all look equal, check that the choke was shutting off(manual choke), checked all plug wires. Have not check the timing yet.

    Trying to figure it out before I go back to the carb guy.
     

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  2. Jul 8, 2018
    heavychevy

    heavychevy Sponsor Sponsor

    Danielsville georgia
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    Sep 7, 2008
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    218
    Todays ethanol wll gum a fuel system in short time. Know it costs more at the pump, but non ethanol is better if, you don't drive it a lot. Stabil makes an additive to put in gasoline, that keeps it usuable longer.
     
  3. Jul 8, 2018
    sterlclan

    sterlclan Member Sponsor

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    what kind of carb? sounds like the low speed jets are dirty, i had a carter that would surge bad,clean he idle jets and no more trouble. did it get anew filter ? how does the filter look? new tank and lines or still the old ones?
     
  4. Jul 8, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    Did you take the carburetor off? Maybe you have a leaking base gasket?

    Holleys are easy to rebuild. Just rebuild it, and don't change any of the settings. Use the same jets, pump shot, power valve, and set the idle mixture. Easy.

    I hae found that the accelerator pump diaphragms are particularly likely to leak after sitting for a whiile. Power valve can also go bad. Get a kit from Holley with the right parts.
     
  5. Jul 9, 2018
    B-Rad

    B-Rad New Member

    Dayton
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    Jun 14, 2017
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    42
    I have not taken the carb off yet, I checked my timing just to make sure it was ok and it was. Guess I will have to take it off and see what I can find.
     
  6. Jul 9, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    NB sitting for a month is not that long.
     
  7. Jul 9, 2018
    sterlclan

    sterlclan Member Sponsor

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    I vote crap in a jet,Or powrevalve
     
  8. Jul 9, 2018
    B-Rad

    B-Rad New Member

    Dayton
    Joined:
    Jun 14, 2017
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    It has a new tank, new filter, carb was rebuilt in the fall. Today I re jet the carb down a little because it's been a little rich anyway. So I check the fuel bowl level and it was at the right level. I unscrewed both the idle adjustment screws and they were all dirty on the needle. Is there something else in that hole to clean? Put it all back together and re adjusted when warm. Still does the same thing.

    Runs out fine, when decel in gear afr goes leand and pops some and almost stalls. When you come to a stop it kind if catchs back up and idles fine.

    Let it sit when I got home for 5 minutes, pressed gas once and it almost started. Pumped pedal again and it cranked for 5-10 sec. then started was rough but smoothed out.
     
  9. Jul 9, 2018
    B-Rad

    B-Rad New Member

    Dayton
    Joined:
    Jun 14, 2017
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    Forgot to mention when going about 30 I put the trans in neautral and let it coast down to about 15 and it was fine.
     
  10. Jul 9, 2018
    sterlclan

    sterlclan Member Sponsor

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    The needle screws into a passageway it may have crud in it. Try a little carb cleaner and air. Safety glasses are recommended
     
    colojeepguy likes this.
  11. Jul 9, 2018
    colojeepguy

    colojeepguy Colorado Springs Sponsor

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    Very important, there's a lot of poor quality knock off Holley parts out there.
     
  12. Jul 22, 2018
    MA74CJ5

    MA74CJ5 Member

    Bolton, MA
    Joined:
    Oct 28, 2004
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    It may be something very simple like a bad fuel filter - I'd start there, you are only out a few bucks and minutes if you're wrong. Next I'd look at needle and float leakage. I'm assuming your tank and lines are in good shape, if your unsure I'd look at that too.

    BTW why'd you pull the original motorcraft carb? I always thought that was one of Jeep's best carbs and more than enough fuel delivery for a 304. Unless you mess with cams and valves, 600 CFM does very little for a 304 and they stink off road.
     
  13. Jul 22, 2018
    B-Rad

    B-Rad New Member

    Dayton
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    The intake and carb were already on it when I bought the Jeep a little over 10 years ago
     
  14. Jul 22, 2018
    turbogus

    turbogus Member

    Albany, Oregon
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    Sep 1, 2014
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    What kind of Carburator is this? Holley, Motorcraft, Carter, Edelbrock Carter clone or Weber?
     
  15. Jul 22, 2018
    B-Rad

    B-Rad New Member

    Dayton
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    Holley 1850-4 I believe. I restarted the adjusting on the carb starting from " factory" and redid the 2 idle circuit screws and adjusting the idle afterwards. Seems to be better, but my afr gauge shows I'm running pretty rich at idle. I guess I will drive it a couple days and pull the plugs and see what they look like. I guess I could aslays jet down one more.
     

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