Holley Electric Choke Question

Discussion in 'Fuel and Air Systems' started by mopowers, Oct 4, 2018.

  1. mopowers

    mopowers Well-Known Member

    Messages:
    3,717
    Likes Received:
    885
    Joined:
    Feb 15, 2006
    Location:
    West Sacramento, CA
    Local Time:
    12:42 AM
    How important is the vacuum signal for the electric choke on a Holley carb? I've noticed Proform and other Holley-type carbs do not have a connection to vacuum.

    Is it to cool the bimetal coil in the choke housing?
     
  2. mopowers

    mopowers Well-Known Member

    Messages:
    3,717
    Likes Received:
    885
    Joined:
    Feb 15, 2006
    Location:
    West Sacramento, CA
    Local Time:
    12:42 AM
    Also, does anyone know what this piston does (circled below)?

    choke.jpg
     
  3. toolmanmike

    toolmanmike FABO Staff Staff Member FABO Gold Member

    Messages:
    32,810
    Likes Received:
    14611
    Joined:
    Jan 18, 2006
    Location:
    Iowa
    View My Photos
    Local Time:
    2:42 AM
    Primary pull off? Just guessing.
     
    • Like Like x 1
    • krazykuda

      krazykuda FABO Gold Member FABO Gold Member

      Messages:
      44,372
      Likes Received:
      9811
      Joined:
      Aug 20, 2007
      Location:
      Orland Park, IL
      Local Time:
      2:42 AM
      That piston moves up and down...
       
    • diymirage

      diymirage HP@idle > hondaHP@redline

      Messages:
      14,073
      Likes Received:
      6367
      Joined:
      Oct 12, 2012
      Location:
      michigan
      Local Time:
      3:42 AM
      not necessarily, you can clock it so it moves sideways
       
      • Agree Agree x 1
      • mopowers

        mopowers Well-Known Member

        Messages:
        3,717
        Likes Received:
        885
        Joined:
        Feb 15, 2006
        Location:
        West Sacramento, CA
        Local Time:
        12:42 AM
        Actually, you can't. It's part of the housing that's affixed to the carburetor.

        I believe the piston meters the vacuum signal. When the engine is cold, the piston is up, not allowing vacuum to flow. When the thermostatic choke coil heats up, the piston moves down allowing vacuum and subsequent air movement to help cool the coil and keep it from overheating. That is my theory anyway.

        Does anyone know for sure?

        My question still remains though- How important is the air flow from that vacuum source if some electric choke housings have it, and some don't?
         
      • diymirage

        diymirage HP@idle > hondaHP@redline

        Messages:
        14,073
        Likes Received:
        6367
        Joined:
        Oct 12, 2012
        Location:
        michigan
        Local Time:
        3:42 AM
        just clock the carb, junior

        clock.gif