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timing/ idle problem

Discussion in 'The Hokey Ass Message Board' started by The Bomber, Sep 6, 2010.

  1. The Bomber
    Joined: Dec 10, 2005
    Posts: 516

    The Bomber
    from mass.

    okay, here goes. have a stock chevy 350 with a brand new edelbrock
    600 cfm with electric choke. start the engine, it idle real high.I haven't
    even touched the idle speed screw yet. I turn the distributor counter-
    clockwise to bring it to the chevy timing specs and it races up more.
    i covered the carb with my hand and the engine almost shuts off, so
    wouldn't this mean there is no vacuum leak. Also wondering if the timing chain has stretched?, etc. Thanks for any info.
  2. I'm kinda curious why you didn't try backing the idle screw down... and if you cover any carb with your hand it'll die.
    Kinda like...
    "Doc, it hurts when I do... this."
    "Then don't do that."

    Also, why was the timing out of spec in the first place?

  3. The Bomber
    Joined: Dec 10, 2005
    Posts: 516

    The Bomber
    from mass.

    Junkyard, the idle screw wasn't even making contact with the throttle,
    plus I had to back off the distributor from the original setting because it would race sky high.I read about putting your hand over the carb for
    a quick test on the forum here.
  4. BulldawgMusclecars
    Joined: Jul 15, 2010
    Posts: 508


    I know you said you hadn't touched the idle adjustment, but the blades must be open already or it wouldn't be racing up like that. Idle will go up when you get the timing close too, so that isn't really a problem. I'd eliminate the carb linkage/throttle plate as a problem before going into other potential issues.
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  5. autometrics
    Joined: Jun 28, 2010
    Posts: 15


    The fast idle screw is on the oppsite side from the idle screw. They always come out the box with a fast high idle closed choke setting. Don't forget to check your throttle cable or linkage.
  6. MBog
    Joined: May 2, 2006
    Posts: 552


    Throttle blades stuck on the base gasket??
  7. tgabbe1934
    Joined: May 20, 2009
    Posts: 64

    from smithtown

    I'm guessing you didn't have this problem before you changed the carb? If not you probaly have a vacuum leak! Check all the vacuum ports on the carb, also what manifold are you running? Is spread bore or square bore? Some manifolds need to run a plate between the carb and manifold if you have a square flange carb on spread bore manifold, even though the bolts line up!
    Also what is your timing actually set at how many degrees? You should have around 36 degrees total with the mechanial and vacuum advance added together! Also check that your linkage or cable isn't bindind on something!
    Good luck and keep us posted on your progress
  8. Ok...
    Was this a running engine before the new carb? Did you replace a similar carb with this one? Is there slack in the linkage/cable? If you put a different type carb on it, the whole thing might be further forward. What about contact with other engine components? I've had Edelbrock carbs, being wider than Holley, that didn't fit past things like the EGR valve, etc and you might have something holding it open slightly. Can you close the throttle any further by hand? If the screw isn't touching, you should be able to close it.
    Another thing might be fuel pressure. If you replaced a different type of carb, you might be running more pressure than this one can hold back.

  9. One more chime on the hung throttle plates. Unbolt carb from intake and see if butterflies close.
  10. The Bomber
    Joined: Dec 10, 2005
    Posts: 516

    The Bomber
    from mass.

    I checked the throttle plate they were close, Autometrics was right about
    the fast idle screw,I forgot to check it,and I should know better,I had an
    edelbrock before,Duh!!! You all were right about the throttle linkage,( a cable one) it was tight just a hair too much. I was able to bring the timing
    back to where it should be, and the vacuum came was back to about 15 lbs. Just for the heck of it I sprayed around th carb and the manifold with
    carb cleaner but the idle didn't increase.BTW, the manifold is a weiand
    dual plane.Thanks to all you Hambers for your help.
  11. 29nash
    Joined: Nov 6, 2008
    Posts: 4,544

    from colorado

    hmmmm. Idle too fast. Remedy. Adjust idle.
  12. davidwilson
    Joined: Oct 8, 2008
    Posts: 595

    from Tennessee

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