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Carb problems

Discussion in 'The Garage' started by bigwalleye, Aug 31, 2005.

  1. bigwalleye

    bigwalleye Registered Member

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    Have a 76 blazer with auto tranny, 350 engine. What version of the qjet does this rig run is it a mv,me - gv,gc - e2se,2se - m2mc - e4me,4mv,m4mc,m4me.
    On the side of the card the only numbers I can find is 17057213awp 1027. I failed DEQ because I is running to rich. What is the proper starting adjustments for this carb?

    Thanks
     
  2. bigwalleye

    bigwalleye Registered Member

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    IT smells very gasy and when I stomp ont it seems to bog than sputter out. It runns great as long as I do not put my foot into it.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    According to the coding, it's a '77 Chev Q-jet, for manual trans.

    I never paid much attention to the 4MV etc breakdown, but it's what I'd consider a standard Q-jet: no electronics/electric choke.

    You got the timing set right? Timing is very critcial, a couple of degrees at idle can make a huge difference in performance.

    Do a search for idle mix adjustment for the Q-jet, it's been covered.
     
  4. bigwalleye

    bigwalleye Registered Member

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    Thanks I set the timing last night. It idels way nicer yet it sit putters out when I hit the gas in drive. I park it revs up with no problems.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    How about a vacuum leak? All that inspected/checks out?
     
  6. big dan

    big dan 1/2 ton status Premium Member

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    same thing happened to mine after i rebuilt it. it turned out to be the spring that keeps the secondary air valve from opening was too lose and the air valve opened too early. i was told that it was hard to adjust the spring and was told to put a spring, similar to the one for the plunger, on the air filter stud over the secondary metering rods and tighten it with a wing nut until the bog goes away. thats how i've been running mine and it runs great.
     
  7. bigwalleye

    bigwalleye Registered Member

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    I think I know where you put it but could you take a pic for me when you get some time. Thanks
     
  8. big dan

    big dan 1/2 ton status Premium Member

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    i would love to take a pic for you but i got two problems. one i don't have a camera and two if i did have a camera i don't know how to put the picture on the computer but i may be able to find a link to a site that describes this with pictures later this evening.
     
  9. bigwalleye

    bigwalleye Registered Member

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    I will take some pics of my carb tonight and point out where I think the sping goes.
     
  10. big dan

    big dan 1/2 ton status Premium Member

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  11. dyeager535

    dyeager535 1 ton status Premium Member

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    There's already a tension spring on the secondaries, passenger side where the throttle shaft comes through.

    It's been so long since I messed with one! Loosen the set screw, and use a flat blade screwdriver to increase tension on the spring, hold in place, and tighten set screw.

    My setup has always been to loosen the spring until tension is so little the secondary air valve stays open by weight, then increase tension slowly, until you get to the point where the air valve closes completely 100% of the time. Test that by opening the air valve with your finger, and slowly releasing pressure. If it hangs up at all, increase tension.

    It is NOT hard to adjust.
     
  12. bigwalleye

    bigwalleye Registered Member

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    thanks for the help. The carb is off a 77 so should have an external canasters connected to it becuase mine does not?
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Some do, some don't. Not sure exactly what determined which applications got a cannister or not (or two) but you'd see the bracket that holds it if it were supposed to be there. The cannisters are just clamped in place by folding the tongs of the mounting bracket tight around a groove in the cannister.

    Now that I think about it though, I would think ALL would need at least one, how else would the choke pulloff work?
     
  14. bigwalleye

    bigwalleye Registered Member

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    It has a munual choke ran off a cable to the cab. If it works not really sure. I just bearly got this truck
     

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