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high idle

Discussion in 'Performance' started by bannock, Sep 27, 2013.

  1. bannock

    bannock Member

    hello everyone

    i havent used my Hijet for about 3 weeks and when I fired her up, it idled really high for a long time. I drove it about 20 miles and it still seemed pretty high. a few days later, i started it, and everything seemed good. Drove to work and noticed it was running high again. Not as bad as before but still pretty noticeable.
    Anything i should look at? or will it just take a bit to work itself out?

  2. rst277

    rst277 Member

    You should look at the side of the carb facing the rear of the truck. Pretty common for the choke assembly to get gunked up and sticky. There is a small toothed wheel that is turned but a half moon curved, toothed thingy that can get road grime and junk in and inhibit it's function. As the coolant heats up the wheel turns making the curved part move and slowly open the choke. If you search sticky choke you'll find a pic. Some lube and a toothbrush/small wire brush will help clean it up. It moves very slowly so sitting and watching can be frustrating as nothing seems to happen. You definitely want the high idle as winter approaches but don't want to drive around with the choke on all the time. I'm in St. James, message me if you want/need a hand or have other Hijet questions. Good luck, Ralph in Winnipeg
  3. TmcLa

    TmcLa New Member

    Good explanation. I just picked up a 93 S83P hijet and having the same issue. I’m gonna give it a scrub and spray some more and see if it helps. When it’s cold it idles up but I wish I can turn that down at least a little. The screw I found that adjusts that setting is all the way out. I don’t have a tach on her yet but it sounds like 1800 or so. I’d just rather it lower in the deer woods You know.
    Josh9022 likes this.
  4. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    You should get a tuneup tach, which hooks up out where you can read it.
  5. Steve S83

    Steve S83 Member

    Jigs-n-fixtures, is there a thread about the Tuneup Tach? My next project and I haven't been able to find much. Thank you.
  6. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    I don’t think so. I tried to track down what i have and can’t seem to find another one on eBay or Amazon.
  7. Steve S83

    Steve S83 Member

    Thanks Jigs. I just grabbed one off the Jungle website that will work. It says 1-10 cylinders so hopefully good. I need some carb setup advice, know anyone on the forum who can help?
  8. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    You need to be sure you’re getting a tune-up tach. Typically the tune-up units measure from 0-1500 or 1-2000. A normal tach measures 0-8,000, 10,000, or even 12,000.

    The normal tach doesn’t have fine enough resolution at low engine speeds to help set the idle mixture, when you’re trying to see changes of 20 or 30-rpm, at around 600-rpm in response to adjusting the idle mixture.

    I remembered the search phrase which works: “Digital Engine Analyzer”. Look for one with an inductive pickup. That lets you get an rpm reading by putting the pickup on a spark plug wire. With some of the engines controlled by an engine management computer, you can’t always get a good signal at the coil to drive a tach.

    The one I have is an ESI 385A, available on eBay and Amazon.

    The next purchase is an ESI 125 Digital Timing light with advance, and tachometer. That lets you verify the vacuum advance and retard ,and mechanical advance curve on the distributor to see if it is operating correctly, and hopefully adjust it if it isn’t.
  9. Steve S83

    Steve S83 Member


    I ordered a regular tach to use mount for daily driving just to know where I’m actually shifting etc. I saw the induction type on Amazon and they were really inexpensive so I’ll grab one as well. You come t makes total sense about not being able to tune with a standard tach. My timing light doesn’t have the tach or vacuum advance built in. Do you k ow if there is a chart floating around that shows what the vacuum advance should be at different RPM’s? I guess once it gets past 10-12 BTDC you really can’t see it on the flywheel anyway so one of those digital tiling lights is kind of a must. Thanks again!
  10. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    The ones I listed are only about $70. So not too bad.

    The digital advance timing light lets you vary the relationship of the light pulse to the timing signal. So, you can adjust it to get the timing light to hit on the zero mark. Which tells you how much advance you have at that time. Checking the advance against what your curve is supposed to be.

    The manual for my truck with the EF-NS engine only lists the initial advance. I’m going to ask the folks over at the livetodai forum if any of them know any better information on the advance curve.

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