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Carb Woes

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Zepplin, Jan 4, 2001.

  1. Zepplin

    Zepplin 1/2 ton status

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    I have a Quadrajet carb on my 350. It doesn't have electric choke. Lately it has been running rich. It idles like crap and I have to put a screwdriver in the carb to hold the choke blade open. I cleaned the carb with liberal amounts of carb cleaner and lubed up the linkages.

    I remember reading on here about adjusting the two screws at the base of the carb to fix a rich/lean problem. Which way do I need to turn the screws to lean out my carb? And, do I really need a rpm gauge and a vacuum gauge to do this?

    Also, is there anything more adjustments I can do to fix the choke blade? All the linkages on the left side move freely but what else could be the problem.?

    This is a real hassle when I have to pop the hood every cold @ss morning and put a screwdriver in my carb. This is also my daily driver.

    Thanks and sorry about the novel.

    74 Blazer
     
  2. ken

    ken 1/2 ton status

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    That year Quad you have uses a "divorced" style choke, meaning it uses heat from the exhaust crossover portion of the intake manifold to constirct a bi-metallic spring and actuate the choke rod and choke "blade". Make sure you have that linkage and that the bi-metallic spring is operable and not frozen up. When I had my '77, I had the same choke, and up in the high sierras on cold mornings I would have to do the screwdriver trick also! Another alternative might be to retrofit an electric choke onto your carb...or maybe even go find a later style carb with electric choke in a junkyard and rebuild it.

    ken
     
  3. HarryH3

    HarryH3 1 ton status Author

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    The linkages aren't supposed to be lubed. That just attracts dust and dirt that will gum up the works. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    The idle mix screws should not be messed with if the problem suddenly starts happening. I would be checking some other choke related items. Whendoes it do this? All the time? If you need a screwdriver to hold the choke blade open, obviously the choke isn't working correctly. Bending linkage is not correct either, as the carbs do not bend themselves, and once bent, you may have a heck of a time getting it right. Do not use the slot on the carbon choke to turn it. Loosen screws and rotate it with your fingers, or it will break. If it only does it while the motor is cold, check the shoke pull off, the diaphraghm may have ruptured in it, which will not keep the choke blade open at high idle.

    Dorian
    My K5 and Chev/Olds links: <A target="_blank" HREF=http://yeagerd.home.mindspring.com/index2.html>http://yeagerd.home.mindspring.com/index2.html</A>
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    An overhaul by a knowledgable person would solve everything. I would find someone around town that has a good reputation. You don't have to overhaul it but its nice just to put down the hundred bucks and cut out every variable. I've had the fun with the pencil too [​IMG]. I was goin to school and right in front is a two lane one way street on a grade near the top of the hill is the front of school. Of course I just happen to stall right in front of while moving to another lane. I have cars flying by me and Im out sticking the pencil in it. I fire it up and stick my head out the window trying see around the hood and make it to where I park. That was a fun deal to have happen in front of everyone. It turns out that almost every part in my distributor was toast and I was running on four cylinders plus a carb in need of overhaul. I only had the truck for three months too. I can't wait to take that hill with 4.11's, I already pull right up it with the 3.08's.

    K5:Big, slow, and flys through snow. [​IMG]
     
  6. Russell Keys

    Russell Keys 1/2 ton status

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    Would it be possible to run a manual choke controller to the carb. this would eliminate the need for a screwdriver, then you could "custom" choke it on those cold mornings. Just a thought.-Russell
     
  7. riz

    riz 3/4 ton status

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    <font color=purple>I was thinking the same thing as Russell, I had a vehichle once with a set up like that and it worked great .......no more pencil it the butterflies !</font color=purple>

    <font color=purple>L8r,

    .Riz.<font color=purple>
     
  8. Toad

    Toad 1/2 ton status

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    The divorced choke is only about $8. I would try that first.
     
  9. Zepplin

    Zepplin 1/2 ton status

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    I went a $6 manual choke cable and NAPA. I rigged it up so I could have a smoother idle when I start it in the mornings. Thanks for all the replies. I really need to rebuild it but, it is my daily driver and I have zero time to do it anyway.

    Thanks again!

    74 Blazer
     

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