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90 YJ 4.2L automatic choke?


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  • 90 YJ 4.2L automatic choke?

    Can anyone give me insight on how this thing works? I can't get mine to work no matter what I try........Do I need to use chicken wire and duct tape or what?

    Any info will help, BELIEVE ME:confused:

  • #2
    Carter carb? I would check the wiring, make sure that you have voltage on the leads to the choke. If not, you have a short or broken wire. If it's just not pulling the choke all the way off when it's warmed up, you probably need a new choke because the spring is too weak. It's supposed to be adjusted cold so that it is in the right spot to make it run right cold. I played with mine for quite a while before I got it to where it ran right at various cold start temperatures. There is some specification on how to set it with a guage cold, but with the varying levels of vacuum leaks in the system, it almost surely will not work right at the spec setting unless everything else is perfect. Let us know if you have any luck.

    1986 CJ-7; 4.6L stroker, balanced & blueprinted; 5" lift, 35x1250 MTRs, Poison Spyder Full Width kit,
    My Jeep

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    • #3
      Re: 90 YJ 4.2L automatic choke?

      Originally posted by justjeepin
      Can anyone give me insight on how this thing works?
      The coil-spring-looking thing inside the automatic choke unit is a heat coil. When voltage is applied, it heats-up, and causes the shaft on which the choke butterfly is mounted to rotate, thus slowly opening the choke as the engine warms up. There are variations of this that use engine coolant to heat the element; but yours is more than likely electric. If there is voltage going to the unit, then check to make sure that the coil is not broken. If it is, then it needs to be replaced. The last time I had to replace an electric choke unit it cost somewhere in the neighborhood of $12. I believe that there is also a cable operated manual choke conversion, but I don't know what it costs for your carburator. The whole thing is desceptively simple. Good luck...