holley 1850 throttle shaft quick question.

Discussion in 'Engine Topic' started by bigblock665, Apr 17, 2011.

  1. bigblock665

    bigblock665 Veteran Member

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    I have a holley 1850... How much slop does the secondary throttle shaft have. Its not leaking vacuum but seems to have some play up and down "not talking about left to right play". And what is the proper way to set the secondary throttle stop?
     
  2. bigblock665

    bigblock665 Veteran Member

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    Iv read 1/2 turn 3/8 turn, needs to be same as primary throttle plates... Does anybody know for sure. I want to get this right before I put the carb on the engine.
     
  3. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    they have replaceable nylon bushings on the secondary shaft...if this is an unknown/high mile carb it may need them replaced.
     
  4. COPO

    COPO Veteran Member Lifetime Gold Member

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    See my page http://www.nastyz28.com/~copo/holley.htm
    From the GM Service Manual Holley Rebuild Pages
    Back off adjustment screw until the throttle plates are fully closed (secondaries). Turn adjustment screw until it just touches the throttle lever and turn 1/2 turn more to position the valves.
     
  5. Damon

    Damon Veteran Member

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    Yeah, half a turn from throttle plates being fully seated in their bores is what I do. It's not exactly like the primary side. There is a small curb idle discharge port and an off-idle discharge slot BUT the off-idle discharge slot should NOT be exposed below the edge of the throttle plates. Primary side they should be slightly exposed, but not on the secondary side.
     
  6. bigblock665

    bigblock665 Veteran Member

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    Thanx I read through it and found I was adjusting other things wrong too! 1/2 turn it is... Ill try this tomorrow because my 4010 is running rich on idle and my idle screws are only 1 1/4 turns out on each.

    I re-bushed my throttle plates today and are nice and tight! Im going to rip of the 4010 and sell it. Its in good shape but I don't need the headache.. Maybe someone can get it right on a different application.

    One more question. I noticed my boosters are a bit larger than my 1850, does booster size have anything to do with throttle response and performance?
     

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