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Carburetor Adjustment - Rochester 2g

Discussion in 'Early CJ5 and CJ6 Tech' started by Steve's 70-5, Jun 26, 2018.

  1. Jun 28, 2018
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    I wonder if my posts from years ago ate still around
     
  2. Jun 28, 2018
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    When I saw the peeling paint on the block I thought about you and saw the wet fuel line. What did you use to seal the joint?
     
  3. Jun 28, 2018
    Focker

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

    WA
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    I just had to trim the end of the line and reclamp. There was the smallest crack in the world that caused the misting.

    I probably over tightened the clamp the first time.
     
  4. Jun 28, 2018
    Focker

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

    WA
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    Just got back from HF.

    New gauge kit with 20% off and a Free 25' tape measure...$12.15 out the door. (y)
     
    Jonbbrew, OrangeCJ5 and OzFin like this.
  5. Jun 30, 2018
    71CJ54WD

    71CJ54WD Sponsor

    DC
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    Drove the Jeep for a while and then hooked it up to vac gauge. Was bouncing all over at around 15. Turned the two low idle mixture screws out slowly and giving it a 5-10 seconds to adjust between turns. After about 2 minutes had a nice solid 20 pounds. Mind you it drove really nice before the adjustment but I took a test drive and it drove even better. Might pop in the side pipes on decel even more now though...guessing turning it out richened the mix. Makes me question the previous owners hei install timing. So tomorrow I’m gonna put the light on the engine and time it to whatever the sticker says. A set of fresh plugs since I don’t know when they were last changed. Then I’ll do the whole vacuum gauge rigamaroll again.

    Hoping to limit the decel side pipe popping but perhaps my issue won’t be fixed until I get a proper exhaust
     
    Walt Couch, CJMark and Focker like this.
  6. Jun 30, 2018
    Focker

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

    WA
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    :clap:
     
  7. Jul 3, 2018
    Focker

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

    WA
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    I have 3 plugged ports across the back of the manifold...Is there a preference of which one to use?
     
  8. Jul 3, 2018
    71CJ54WD

    71CJ54WD Sponsor

    DC
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    I didn't look around too much because I have a port plugged that I believe went to heat - so used that. Its easy enough to hook up to each and rap the throttle to see if they react the same.
     
  9. Jul 3, 2018
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    FWIW
    I had a gard time getting the timing right on Animal after the rebuild.

    Look at the dist lobes for wear, my timing was all over the place.

    HTH
     
  10. Jul 3, 2018
    Focker

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

    WA
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    Vacuum adjusting is fun...It feels like a just dropped a 4.3 FI Vortec in my Jeep!
     
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  11. Jul 3, 2018
    71CJ54WD

    71CJ54WD Sponsor

    DC
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    I agree. I definitely did it really quickly and need to go back. I am not sure its possible to fix: I have popping coming out of 1 of the 2 side pipes. Only the driver side pops on decel. Hopefully a timing light, idle adjustment, and vacuum tune, all done together, will help. Is there any info in our forum regarding timing settings for the HEI distributors? The previous owner installed it and I really don't know anything else about it.
     
  12. Jul 3, 2018
    Focker

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

    WA
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    Here are my specs...

    Plugged vacuum line (to vacuum advance).
    Idles at 650 RPM.
    Timing at 9*.
    Under acceleration it's at 17*.

    Connected vacuum line.
    Idles at 650 RPM.
    Timing at 9*.
    Under acceleration it's at 32* max.

    For more info start here on post #57
    Post #57 of the HEI distributor cap #1 terminal
     
  13. Jul 7, 2018
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    I set the timing per the SM. Got a vacuum gauge and have 17-18 vac. at idle. I adjusted the carb with vac gauge, while the vacuum house was plug into the distributor.

    Dove the Jeep, runs better. Under a quick/heavy acceleration there is a hesitation/stumble at the beginning, then it picks up and runs great. Any idea what needs to be adjusted for the hesitation.

    I have a rebuilt carb I got off ebay
    V-6
     
  14. Jul 8, 2018
    Beach66Bum

    Beach66Bum 1966 Tuxedo Park Mark IV 2024 Sponsor

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    Sounds like the accelerator pump.
     
  15. Jul 8, 2018
    Hellion

    Hellion Regurgitated

    Eastern TN
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    Great thread--many thanks. Will be re-reading the finer points in the near future.

    Mine has run rich since purchase, basically the passenger side bank, noticeably belching rich fumes and has always started each and every time without choke. In fact the choke cable was seized in the off position. I think the PO may have enriched the mixture to make it easy to start...
     
  16. Jul 8, 2018
    NCRenII

    NCRenII yellow fever

    Far Nor Cal
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    I am sorting out rich condition as well. Low mileage original carb, rebuilt, new brass float, needle and seat. all passages clean and clear no shaft wear, but gassy odor suggests rich condition.
    I'm working out one system at a time. Vac check, Timing check, float level check, bb re-seated, and fuel pressure checked. I will next make sure the pump to tank return line is intact and flowing and install a just sourced new power valve. I'm also looking at how to de-carbon the air injectors from the pump to the combustion chamber.
     
  17. Aug 11, 2020
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    Going back to this thread, its hard to believe I was fooling with the carburetor 2 plus years ago.

    Going to list what is going on and what I have.

    I bought a Rochester 2G on Ebay, the first time I put it on "2 years ago" I thought it was running rich, the Jeep would stumble when you accelerated. Did some work to Jeep and now I am running/ driving it again, still doing the same thing. Had a Carb shop in town look at the carburetor and he said everything looked OK.

    CONDITIONS NOW
    I used a vacuum gauge and am reading between 17 and 18 on the gauge, Jeep still stumbles when you accelerate. The adjustment screws are out about one turn.

    Timing set at 5 BTC. The engine was rebuilt and I have a after market timing cover. The gauge to show where timing is set is bolted on. Is the gauge is showing right timing?

    Pulled a spark plug and it is black as coal.

    GOING TO THROW A LOT OF IDEAS OUT, WHAT DO YOU THINK.

    After looking at spark plug, engine is running rich.

    Is timing right?

    Carburetor Jetting right?

    Distributor cap and rotor need replacement? Came with engine/Jeep, did not replace at rebuild, looked new.

    Just put fresh gas in Jeep, used "pure gas" no alcohol.
     
  18. Aug 11, 2020
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    sounds like you need to pull top off carburetor and see what jets are installed . might have been for a V8
     
  19. Aug 11, 2020
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
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    First thing I would do is, (with the engine off but recently been operating), remove the air filter assembly, open the throttle by hand and look for two streams of gas to be squirted out the accelerator pump nozzles and into the throat/ venturi's.
    Note:the float bowl has to be full or nearly full when you do this.
    Stumbling upon acceleration is a classic sign of accelerator pump issues. Some (many) carburetor pump materials are not very resistant to ethanol.
    This test is relatively easy and doesn't cost anything but time and a little effort. If yours turns out okay you can at least remove it from the potential problem list and move on to the jets as Ron said.
    Look for any potential vacuum leaks too.
     
  20. Aug 12, 2020
    colojeepguy

    colojeepguy Colorado Springs

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    Set mixture screws and timing for the best vacuum reading & see how it runs.
     
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