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Intake/carb Mating

Discussion in 'Early CJ5 and CJ6 Tech' started by Andrew Theros, Apr 16, 2022.

  1. Apr 16, 2022
    Andrew Theros

    Andrew Theros Member 2023 Sponsor 2022 Sponsor

    Los Osos, CA
    Joined:
    Feb 24, 2021
    Messages:
    393
    519C1909-20AE-41EF-A30F-BB1F4EEAE275.jpeg Hi everybody!
    Finally got my oil pump woes squared away, but now I have terrible hard starting issues. When I do get it running, she’s running very rich. To the point, when trying to start, the backfires bring the Sheriff’s deputy to the neighborhood!
    Once running, she runs nice, just way rich.
    I decided the 2G needs some help. The fuel filter always has rust sediment in it (I clean it often), I figured I sucked a chunk through and caused my “carb issues”
    Anyhow, pulled the carb and found this.
    Can I plug the intake holes with an oily rag and wet sand the rust?

    Next question, what are those small passages on the sides? They feel like they go nowhere, but I didn’t dig to deep until I vacuum out the sediment.
    A rebuild kit from Mike’s carbs will be coming soon as well as a tank removal for cleaning and inspection.

    As usual, looking forward to your advice!

    Thanks,
    Andy
     
  2. Apr 16, 2022
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
    Joined:
    Jul 16, 2007
    Messages:
    938
    Yes, you can stuff the intake while cleaning up.
    Many manufactures engines of this vintage have an exhaust crossover port in the intake manifold to aid in warming up the manifold / carburetor so that the fuel atomizes better and stays in the form of a vapor. Cold intake manifold's, cold carburetors and cold air can cause the atomized fuel from the carburetor to condense and pool as a liquid in the intake manifold and this is a way to add heat to the base of the carburetor to deal with that issue.

    The Dauntless 225 Rochester carb has a portion of its iron base that allows passage the hot exhaust gases through it from the ports in the manifold, this is done to to aid in warming the carburetor.
    Unfortunately the corrosive exhaust gases tend to rot away two of the carburetor mounting studs or cause them to be seized into the manifold.
    The corrosive exhaust gases cause the rust on the intake.

    [​IMG]


    I tapped and plugged off the ports in my manifold because I don't drive my C101 in the winter.

    [​IMG]

    You could leave the ports carboned up as they are, or clean them out to restore full flow, or plug them off.
    The studs or bolts that have the exhaust gases pass over them should be stainless or brass and use an anti-seize product on them too.
     
    Last edited: Apr 16, 2022
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  3. Apr 16, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    Note that you should have no exhaust flow in that passage unless the heat riser in the exhaust pipe is stuck closed. With the heat riser open, there is only passive contact with the exhaust gases, not flow through the intake manifold, once the exhaust heats up.

    Living in California, even mid-coast, you don't need the heat riser. Buffalo NY, yes.
     
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  4. Apr 17, 2022
    boopiejones

    boopiejones I can’t drive 55

    California east bay
    Joined:
    Mar 16, 2020
    Messages:
    545
    I was going to plug those holes, but then I got lazy and ordered a 1/4” thick gasket with the hopes it would block the holes off and not get burned up by any hot exhaust gasses. I’ve driven it about 1,000 miles and it seems to be holding up just fine. That said, my exhaust doesn’t have a heat riser valve, so I’m not sure any hot gasses are flowing through those holes anyway.

    Regardless, with California weather I haven’t had any issues with the carb not getting up to temperature quickly enough. I have a manual choke that I fully choke for start up. Engine turns over immediately, and then I quickly bump the choke knob down so the air isn’t choked but I still have a high idle. After about a 1/2 mile of driving, everything is warm enough to fully release the choke.
     
    Last edited: Apr 17, 2022
    Andrew Theros likes this.
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