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Technical Vacuum Advance on carburator

Discussion in 'The Hokey Ass Message Board' started by White_Attack, Jun 18, 2019.

  1. Having an issue with my Carter AFB where the vacuum sucks while idling and not while accelerating.
    How do you stop this from happening? How do we keep it from sucking in idling position?
  2. LM14
    Joined: Dec 18, 2009
    Posts: 1,937

    Member Emeritus
    from Iowa

    What's wrong with advance at idle?
    Montana1 likes this.
  3. Get a vacuum gauge and check the vacuum ports on the carb to find one with ported vacuum instead of manifold vacuum. Then hook that port up to the distributor advance.
  4. Scumdog
    Joined: Mar 3, 2010
    Posts: 627


    That's exactly how it should be - the lighter the load on the motor the more advance you get, the more economy you get - and that's just one advantage of using manifold vacuum.
    Montana1 likes this.

  5. boltupal
    Joined: Dec 27, 2010
    Posts: 279

    from western ny

    Vacuum advance needs to connected above the throttle blades. { spark ported}.
    egads likes this.
  6. distributorguy
    Joined: Feb 15, 2013
    Posts: 45

    from MN

    When you're accelerating, your engine vacuum drops to near zero. No vacuum advance under load is what you want, and its virtually impossible to set it up any other way. Try driving around with a vacuum gauge in the passenger compartment for a while so you understand what's actually happening. Switch between manifold and ported vac to see its exactly the same except at idle.
    If your ported vac had a signal at idle, either your throttle is open too far and its unshrouding the port, or the bushings are shot and the throttle blade is no longer covering the hole.
    Montana1 likes this.
  7. town sedan
    Joined: Aug 18, 2011
    Posts: 1,290

    town sedan

    Timed vacuum above the throttle plates. Manifold vacuum below the throttle plates. Which do you want?
    Jalopy Joker likes this.
  8. Deuces
    Joined: Nov 3, 2009
    Posts: 21,294

    from Michigan

    I always went with full time vacuum.... Never a problem...
    OLSKOOL57, Montana1 and i.rant like this.
  9. Truck64
    Joined: Oct 18, 2015
    Posts: 5,094

    from Ioway

    Scares the womenfolk and horses.
    White_Attack likes this.

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