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Carb Tuning Help

Discussion in 'Early CJ5 and CJ6 Tech' started by termin8ed, Aug 29, 2017.

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  1. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    Seems every time i get something adjusted closer, something else is out. I went thru the carb again and found the powervalve bent, so swapped out that with another i had. Accelerator pump looked good. There is no spring coil around the rubber part of the pump on this one.
    I have the idle set around 600ish rpm. Timing looked like it was on.

    Now im getting the hesitation when you hit the throttle. Slowly accel and seems good. I know it seems like accel pump issue, but what should i adjust?
     
    termin8ed, Aug 29, 2017
    #1
  2. Aug 29, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Is there any sort of adjustment on the arm? Is the lack of a spring hampering fuel delivery?
     
    Glenn, Aug 29, 2017
    #2
  3. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    [​IMG]
    Its not the return spring above. Ive had one before where it has a spring maybe 1/8" diameter coiled around inside the pump rubber. Dont know. The pump rubber did have a little up and down "slop" to it?
     
    termin8ed, Aug 29, 2017
    #3
  4. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    I did try bending the pump rod a little longer and it didnt seem to do anything. Shortened it and it just brought the idle up because it didnt let the throttle plate close all the way
     
    termin8ed, Aug 29, 2017
    #4
  5. Aug 29, 2017
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    What are the aur mixer screws set to?
     
    Focker, Aug 29, 2017
    #5
  6. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    Not sure. Should be 2 turns out i think
     
    termin8ed, Aug 29, 2017
    #6
  7. Aug 29, 2017
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I'd be considering that to be the problem.
     
    Glenn, Aug 29, 2017
    #7
  8. Aug 29, 2017
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    I fought issues with mine, but if the choke was slightly on it was fine. Play with the mixer screws. Check the cleanliness of the power valve.
     
    Focker, Aug 29, 2017
    #8
  9. Aug 29, 2017
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
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    Sure sounds like accelerator pump.
    To check its operation look down the carb throat and open the throttle briskly, you should see two streams of gas squirting out the accelerator pump nozzles, one stream down each venturi. This can be done with the engine off or running but can only be done a couple of times if its off before the pump well empties.
     
    OzFin, Aug 29, 2017
    #9
  10. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    I'll pull the top off again and check the pump. Anyone know off hand know what size the pump is? Mikes carbs site shows 2 that. Are close. I dont have the carb number anymore.
     
    termin8ed, Aug 29, 2017
    #10
  11. Aug 29, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    It does. But I had it working good before I messed with it last week. Thats whats getting me. Maybe its a combination of lower rpms, idle screws not on enough, and that small amount of slop with the pump diaphram...
     
    termin8ed, Aug 29, 2017
    #11
  12. Aug 29, 2017
    tarry99

    tarry99 Member

    Northern California
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    Put a few more degrees of timing in the motor.............See how it likes it.
     
    tarry99, Aug 29, 2017
    #12
  13. Aug 30, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    Mixture screws where about 1 1/2 turns out. I found a rebuild kit in my toolbox at work with extra parts and it actually had that garter spring that goes around the pump diaphram. The diaphram stays in one place now. Ill toss that back on tonight and see what it does. I'll play with timing after that.
    1 thing at a time...
     
    termin8ed, Aug 30, 2017
    #13
  14. Aug 30, 2017
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    X2
     
    Focker, Aug 30, 2017
    #14
  15. Aug 30, 2017
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    That blue acc pump without garter spring is a normal production ethanol unit and they all have some slop in them. Does not create a problem. If you get two healthy squirts of fuel from the venturi assy then the acc pump circuit is good. YOU SAID IT HAD A BENT POWER VALVE? I think you mean power piston rod. The power valve screws into the bottom of the bowl and has an extremely short pin with a spring mounted inside the valve housing. I think the power piston is hanging in the down position not allowing enough fuel after the acc pump has done it's thing. They have to work in tandem.
     
    Walt Couch, Aug 30, 2017
    #15
  16. Aug 30, 2017
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    During idle and cruising ranges, the relatively high engine vacuum holds the power piston in the up position against tension of a calibrated spring located on the power piston stem. During this period, the power valve remains closed.
    Increases in engine load lower the manifold vacuum. When it has dropped sufficiently, the power piston spring overcomes the upward vacuum pull and the power piston moves downward, opening the power valve to allow additional fuel to flow through the calibrated restrictions and on into the main well area. The fuel flowing through the power system supplements the fuel passing through the main metering jets to give the proper mixtures required for power operation.
     
    Walt Couch, Aug 30, 2017
    #16
  17. Aug 30, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    That makes sense. Yea, it was the rod, not the valve that was bent. I swapped that out with another i stole from a spare carb. Thats the one thing i changed other than dropping rpm's down.
    How would you go about testing that?
    Thought i made sure the passage in the top of the carb was clear. Unless i have a cut or torn gasket?
     
    termin8ed, Aug 30, 2017
    #17
  18. Aug 30, 2017
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    The cavity for the piston gets scaly and crusty and won't let the piston slide up and down freely and quickly. Also polish the piston itself. Will make a big difference.
     
    Walt Couch, Aug 30, 2017
    #18
  19. Sep 14, 2017
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    Well, finally drove it to work today.
    Man what a difference. Drives good, idles down lower, no stumble.
    All i need to do now is bend the gas pedal so it not hanging up so high.

    Really need to look into the floor mount setup for the v6
     
    termin8ed, Sep 14, 2017
    #19
  20. Sep 14, 2017
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    (y)
     
    Focker, Sep 14, 2017
    #20
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