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Black smoke out of new Crate motor

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Boss, Jun 12, 2000.

  1. Boss

    Boss 1/2 ton status Author

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    I noticed the other day that I had black smoke coming out my exhaust. My motor is a brand new crate 350, with just about 1000 miles. I remember this topic being brought up before but didn't pay much attention to it. Anyways, why is this, and what does black smoke represent? As always, thanks.
    Boss
     
  2. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Not positive on this but it sounds like it may be running too rich. See if you can have some lean your carb a little. What carb on you running anyways?

    Shawn
    87 K5
     
  3. Boss

    Boss 1/2 ton status Author

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    Shawn,

    I'm running a rebuilt Rochester Quad Carb.
    Boss
     
  4. Burt4x4

    Burt4x4 3/4 ton status

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    I'm thinking it may be your air/fuel mixture.
    readjust and see if that helps....
    if not get a piece of cardboard and place it in frnt of you exahust tips and see if oil is spitin out, if it is get a new motor your rings didn't seat properly and your warrinty should cover that, I think!?

    Good Luck!

    Rock ON![​IMG] 72 K5 [​IMG] Led Zeppelin
    http://burt4x4.coloradok5.com
     
  5. smack

    smack 1/2 ton status

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    Maybe you outta have a look at your plugs because the evidence will be more straight-forward. If they're black and sooty, it's too rich. If they're oily, start thinking about returning the motor.
    good luck
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Black smoke = too much fuel.
    White smoke = oil.

    It's running too rich. Have the carb tuned for that particular engine and it should run like a champ. If the engine has a hot cam, it can cause the power circuit to come in too early. The lower vacuum the cam creates will fool the stock power valve into thinking the throttle is open further than it really is. The power valves are available with different vacuum ratings to correct for this.

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     

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