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2 Jet Runs Better With Choke On Plus HEI Issue

Discussion in 'Early CJ5 and CJ6 Tech' started by Focker, Feb 18, 2015.

  1. Feb 18, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

    Tri-Cities WA
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    I just completed a HEI conversion and now need to dial in the Rochester 2 Jet (2G). It's been cleaned and there's a new accelerator pump installed.

    Starting sequence is as follows:
    - Pull the manual choke knob all the way out.
    - Pump the gas a couple of times...Fires right up every time.
    - Adjust manual choke until things settle down to 650-700 RPM.
    - Push the choke knob all the way in.

    Issue:
    - Rev the gas and sputter/pop...Feather the gas = No problems.
    - Pull the choke out just a bit...Rev the gas and it's perfect.

    I've messed with this thing and I can't emulate partial choke. The mixture screws are 2 turns out max. When looking down inside the barrels there's no stream, it's more of a dribble.
     
  2. Feb 19, 2015
    Danefraz

    Danefraz Well-Known Member Sponsor 2019 Sponsor

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    Did you do a tear down, soak, rinse and air to the passages or just new pieces? Sounds like gunk in a passage, but I'm not a carb guy. I took mine all the way down when I did it. Ran like a top until I stared the frame off stuff.
     
  3. Feb 19, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Complete tear down, soak and thorough cleaning of every orifice.
     
  4. Feb 19, 2015
    uncamonkey

    uncamonkey Member

    Greeley CO
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    As they say, you don't do 2 changes on a motor at the same time. It's a bit hard to figure out later.
    From the choke bit, it sounds like you have a vacuum leak somewhere or a gasket in the carb isn't the right one.
     
  5. Feb 19, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    It had this symptom prior to the HEI conversion, I've just been living with it. I just recently discovered how it doesn't have issues with partial choke.
     
  6. Feb 19, 2015
    Danefraz

    Danefraz Well-Known Member Sponsor 2019 Sponsor

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    Hmm, vac leak or air getting into your fuel line? Shooting in dark here.

    i recall mine fumigating and sputtering when running until I rebuilt, and the bb under the accel pump (?) Or the other one was lodged tight, seems, but I don't recall, mine was full of mud in the bowl and needed major help?

    i had about six extra seals for the different variations left over from my kit. I saved my old ones to match the replacements. A couple were pretty close. Possible you got one slightly close?

    used to older two stroke small,stuff, usually a clogged jet type thing, fix was twist needles all way in, and bottom, spray with carb cleaner, then back out again, spray again sort of thing, I'm sure yours have been in and out more than you want.
     
  7. Feb 19, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    I think I'll order a overhaul kit and Go through the whole thing. I didn't clarify earlier but it's been 7 months since I cleaned the carb. I went through it right after buying the Jeep. The PO put in the new accelerator pump. A coworker told me tonight that he has a close friend who can work wonders on carbs. I'd like to learn what to do myself but maybe he wouldn't mind giving me some guidance while making a little $ too?
     
  8. Feb 19, 2015
    homersdog

    homersdog Tulsa, Ok Sponsor 2019 Sponsor

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    If everything is set right, then it shouldn't do this. If it is the original carb about all you have to do is make sure it is very clean, replace the accelerater pump, check valve, use the corect gaskets throughout as you rebuild, MAKE SURE the float is working properly and is set to factory specs.
    Also make sure the accelerator pump connection is correct and not hanging up in side the housing. Disconnect it from the pedal linkage and operate it by hand to make sure the pump is squirting through its whole stroke. Getting this pump right is PITA but makes all the difference.
     
  9. Feb 19, 2015
    47v6

    47v6 junk wrecker! Sponsor

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    My 2 GC was totally wore out and I replaced it with a holley 4 barrel. One of my main issues was throttle shaft needing to be rebushed. It was oval shaped. No amount of tuning was helping it and as the shaft turned and where it stopped changed the air flow mixture. I tried to fix it but destroyed it. A remanned one is 300 bucks. They "should" come with a rebushed throttle shaft. I know, thats too much money and I agree.

    So, you need to check for vacuum leaks. Carb cleaner sprayed at the base of the carb will make your engine do different things depending on the type. Explodey kind will make it rev. Maybe blow up too if you're not careful, so be careful. Make sure your vac lines are connected and in good repair.

    Go get a vacuum gauge. They are like 20 bucks at Harbor fight. Read how to use one online and it can tell you a lot bout the condition of your engine.

    I ended up really having 2 options, try fixing and cobbling together old wore out 2GC's ,all of which were slightly different and in various stated of destroyed, buy a remanned 2GC for 300 bucks or buy a Holley on sale for 415 bucks with an offenhauser intake I got for 50 bucks.

    I went with the hooley had issues too.
     
  10. Feb 19, 2015
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor 2019 Sponsor

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    A common mistake when rebuilding the 2g series carbs is the two check balls. Be sure the small check ball goes in the channel under the accelerator pump and the spring seats all the way down in the groove. This keeps the check ball from popping out of the channel.
     
  11. Feb 19, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Hmm...

    I really thought my partial choke situation was different from all the posts I found and read yesterday. So basically if partial choke is engaged, it could be making up for a vacuum leak? Or the second most suggested cause I read about, are the check ball(s)? I'm off tomorrow and plan to figure this out. Thanks for all the suggestions and advice.
     
  12. Feb 19, 2015
    AKCJ

    AKCJ Active Member

    Fairbanks, Alaska
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    My ideas:

    vacuum leak
    check balls
    accel pump adjustment

    I've read that if your vacuum advance (or mechanical advance) pulls in too quick that can cause a stumble. Check by plugging the vacuum advance and by checking with a timing light and tach. Shouldn't advance till you get to about 1200 - 1500 rpm.
     
  13. Feb 19, 2015
    jeep2003

    jeep2003 Active Member

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    mine does that too until its fully up to temperature. it does like a little bit of choke sometimes
     
  14. Feb 19, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    I just got off the phone with my coworker's carb guy. He guarantees he can dial in the carb, timing, advance & curve. He said it'll cost about $200 - $250 and he'll let me watch!
     
  15. Feb 20, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Picked up a rebuild kit and a Ultrasonic Cleaner from HF after checking for vacuum leaks, non were found.

    Going to bring this thing back to life!
    [​IMG]

    [​IMG]

    Cleaning the parts as I type...The rebuild is next!
     
  16. Feb 21, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    I love the Ultrasonic Cleaner I bought from HF!
    [​IMG]

    I didn't get to try the Jeep until this morning. I'm not sure what was the root of my carb issue, here's what I do know. I didn't know I could remove the power valve with a screw driver until I was almost finished with the rebuild. I'm glad I did, there was crud trapped under it. The float wasn't set to specs either.

    What I know - This things runs great now! I basically bolted it on this morning and it fired right up. The only adjustment was setting the idle once it was up to operating temp. AWESOME! I have to give a shout out to "Mikes Carburetor" for his online rebuild videos. I would have a harder time figuring out where all the things go...You never know if the guy(s) before me did it right.

    Do you guys suggest I recheck my timing? <--- This might a no brainer...Right?
    Edit - Checked it...It's spot on!
     
  17. Feb 21, 2015
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor 2019 Sponsor

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    Glad you are finally satisfied with it. Good show.
     
  18. Feb 21, 2015
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member Sponsor 2019 Sponsor

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    Yeah.
    I just want to be able to focus on other things and have the Jeep not be a chore to drive.

    Here's a question tho. I hijacked a recent HEI thread. I mentioned returning from a test drive just in time to run out of gas in the driveway. Turns out, I didn't run out of gas. Today I was waiting for someone and was just idling in the parking lot and it did it again. The jeep didn't sputter, it just stopped running. I started it back up and drove home. Any ideas?
     
  19. Feb 22, 2015
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    Sounds like a bad HEI module, used to see that fairly regularly when there were still a lot of vehicles with that system.
     
  20. Feb 22, 2015
    47v6

    47v6 junk wrecker! Sponsor

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    Napa Does carry the correct buick odd fire module. It comes with silicone grease, throw that out or use it on spark plug boots. Silicone is an insulator. Go to radioshack before they go out of business and buy the heat sink paste. apply liberally to the back of the module and install. 1975 Buick sky hawk 231 oddfire ignition control module is what you want.
     

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