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Me and my Carb

Discussion in 'VB - VK Holden Commodore (1978 - 1985)' started by Goon, Jul 28, 2006.

  1. Goon

    Goon Scientific Tuning

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    Hey all

    Well i have a carb problem its something ive done in the past and i know what it is but now i just cant get it right again.

    Okay my timing is perect 6 deg, but when i start my engine on first go the auto choke kicks in and does its thing, though i touch the pedal once and she dies and cant idle properly, shes trys but can't... I've even replace the accelrator cable, any tighty on the cable and itll be holding the throttle abit.

    It's like my idle screw isnt connecting with the high idle cam piece on the side of the carb after each push of the pedal.

    I've heard the mixer screw can be done by listing when shes dies on turns etc.. but what if she doesnt die and i could turn that screw in and out and still the same idle? Thats what its like.

    Mty rides due in for insepction nextweek and i cant even get her to idle right :(

    Any help would be great.. maybe default settings for the carb screws?

    ps. i have headers
     
  2. Goon

    Goon Scientific Tuning

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    Others changes ive made

    Topgun 8mm leads in exchange for new bosch leads which are shorter.

    Disconnected the aircon plunger
     
  3. vkberlina

    vkberlina VK Madman

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    Ok I guess your talkng about a Varajet II carb, there are several idle adjustments on the varajet

    When the choke coil is cold, ensure the fast idle screw is on the second highest step of the cam. Now check the choke valve in the top of the carb there should be around a 2mm gap beteer the body of the carb & the butterfly. To adjust this bend the choke linkage arm, if oyu have fiddled with the idle adjust screw you will need to reset it back to factory then bend the choke arm to adjust.

    Now have the engine at normal running temp, and that the choke is fully open. Make sure the throttle cable is adjusted correctly, car is in neutral or park, aircon off. Now adjust the idle using the 2 idle screws the top one is an air bleed and the botton is a fuel rate. For a starting point adjust top screw (air bleed)screw it in untill seated then back it out 2 full turns. Next scre the fuel rate screw in then back it out 3 full turns. Fine tune from there.

    Fast idle can be adjusted by having the idle adjust screw on the lowest step on the idle cam, check the idle speed & adjust it accordingly.

    cheers
    Scott
     
  4. Goon

    Goon Scientific Tuning

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    Yeah mate is a Varajet 2 carb, cheers anyway ill give this a go :)

    When u say 2nd highest step do u mean its at the mark were number 2 is printed on the cam ?
     
  5. vkberlina

    vkberlina VK Madman

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    number 2 isnt printed but from memory there are 4 steps on the cam so the 2nd highest would be the second from the top.

    cheers
    Scott
     
  6. Goon

    Goon Scientific Tuning

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    Thanks mate
     
  7. Goon

    Goon Scientific Tuning

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    Okay i know of the fast idle and mixture screw which would be fuel?

    One of the screws as said above i cant find.. its the only thing holding me back atm.
     
  8. Goon

    Goon Scientific Tuning

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    Nevermind i found a diagram :D
     
  9. Goon

    Goon Scientific Tuning

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    Is there a certin way to bend the choke arm?

    Atm i got the mixture screw set a 3 turns

    The idle screw when it sits on the lowest cam its set at 1200rpm for N/P
    850 rpm when in gear

    MY issue is atm its in N 1200rpm, i push the pedal once and it dies. I think i may have to bend the choke arm?

    EDIT** The idles fine until the screw leaves the idle cam after a touch of the pedal. "idle cam go's up, screw comes back and has nothing to keep the revs up"
     
    Last edited: Jul 29, 2006
  10. Goon

    Goon Scientific Tuning

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    Well overall so far it looks like my cars anti rev while in N...

    I'm going to take it for a tiny test drive today to see if it cuts out when i push the pedal down during drive.

    If my fast idle screw had something to come back to after a push of the pedal while in N i'd be 100% good.
     
  11. Goon

    Goon Scientific Tuning

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    Okay all good so far, special thanks to scott for the big help :thumbsup:

    Atm this is my 2 choices of idle

    - 1150-1200 N "low idle but sounds kind of like a plane"
    - 850 D

    OR

    - 850-900 N "putt putt sound"
    - 650? D <<-- didnt test it for that long

    It's currently set with the first setting.

    Any advice?
     
  12. Goon

    Goon Scientific Tuning

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    reset the timing and re-did it again, timing all done, starts first go etc.

    But would anybody know the default settings for the idle screw? "eg. number of screw in etc" and plunger? the plunger is the a/c soldnoid. my current idle is between 1200-1500 in N, just trying to get it around 850rpm without the idle screw slipping off the idle cam.
     

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