Tuning Solex 28 IBT
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  1. #1
    Tadpole HeyCharger's Avatar
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    Default Tuning Solex 28 IBT

    Hi guys. I just installed this carby, plus manifolds on my 4CV. I can't seem to find how to tune or adjust mixture. There is a screw at the base, which seems to adjust idle mixture. Runs great at idle, but as soon as I apply throttle, it dies. Any leads appreciated. Thanks. Rod.

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  2. #2
    1000+ Posts Dave's Avatar
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    Usually you can only adjust idle mixtures with a screw. For mixutres with more throttle applied you are looking for correct float level and jets. Assuming jets are standard you should check the float level to be within spec.

    My experience with carbs though, is that everything is probably set right, you just need to strip everything down and clean it out. There is likely to be crud in the fuel bowls that is getting sucked into jets etc.

    Dave


  3. #3
    1000+ Posts Wildebeest's Avatar
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    Default Solex 28...

    Quote Originally Posted by HeyCharger View Post
    Hi guys. I just installed this carby, plus manifolds on my 4CV. I can't seem to find how to tune or adjust mixture. There is a screw at the base, which seems to adjust idle mixture. Runs great at idle, but as soon as I apply throttle, it dies. Any leads appreciated. Thanks. Rod.
    Rod,
    Has the emulsion tube / air bleed holder "gone walkabout?" Visible down carb throat.
    They tend to come loose/fall out if laying around.
    I think they are too small a carb to have a removable venturi. Is it in place?

  4. #4
    1000+ Posts Fordman's Avatar
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    Does it have an accelerator pump circuit? First suspect for flat spot. To check - open throttle quickly while looking down throat (engine off). Should see squirt of raw fuel across throat.
    2004 Scenic I 2.0 auto (Hers)
    2016 Ford Territory (His)
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  5. #5
    Tadpole HeyCharger's Avatar
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    Now keeping in mind that I'm NOT a mechanic. By looking at diagrams etc, I believe I am missing the "jet" part of the main jet. Remember this carby came in pieces and I'm just trying to put it all together. Getting back to the main jet. There is nothing inside the housing. I unscrew the cap and I would think there should be a jet there. But it is empty. Where do I buy these (preferably in the Sydney area).

  6. #6
    1000+ Posts Dave's Avatar
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    Any photos to confirm?


  7. #7
    Tadpole HeyCharger's Avatar
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    Ah ha. I'm missing "part 70".
    Anyone know of Dauphine wreckers in Sydney area? I might try and buy another carby.
    Attached Thumbnails Attached Thumbnails Tuning Solex 28 IBT-solex2.jpg  
    Last edited by HeyCharger; 8th June 2012 at 08:56 PM.

  8. #8
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    Default Jet !

    Hi,
    If the jet is missing, which is quite likely, then you will need to find what size was fitted. The jets are removable so they can be changed, at the factory to suit different models etc.

    They have the size stamped on them. The usual size range would be around90, 95, 100, 105, through to perhaps 140 in steps of 5 (or 2 sometimes). Someone on AFs would probably have some from old carbys. I have a few I think. See if you can find out what might have been the factory size. If all else fails fit a 120.

    The engine will choke on lots too much fuel without it as its purpose is to meter the correct amount of fuel. However I doubt it would cause the problem you have. Perhaps one of the other jets is blocked or ??
    jaahn

  9. #9
    Tadpole HeyCharger's Avatar
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    Hi jaahn. I think the missing jet is the main problem and I did actually blow out some crud from the inlet line. According to my "Tune-Up Charts" the Dauphine main jet was 92.
    On searching the 'net, I found this "The Brosol H30/31 replaces the 28 series," Has anyone done this? Overseas they are reasonably priced. Rod.

  10. #10
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    Quote Originally Posted by HeyCharger View Post
    Hi jaahn. I think the missing jet is the main problem and I did actually blow out some crud from the inlet line. According to my "Tune-Up Charts" the Dauphine main jet was 92.
    On searching the 'net, I found this "The Brosol H30/31 replaces the 28 series," Has anyone done this? Overseas they are reasonably priced. Rod.
    Hi Charger
    You have the jet size, see if anyone on here can supply. Any jet 90 to 100 would get you started and see if it runs. I will look in the shed.

    The Brosol H30/31 is a replacement carby for VWs. It may not fit your stud pattern and the linkage will be different and it may be facing the wrong way so I would not rush into it. Solex made carbys for everyone in the world, over a lot of years so just any old one is unlikely to be a good fit or run well.

    If you have a problem lifting the revs off the idle it is likely to be the progression system. That,s the jet 74 and the associated passages. Is the tiny hole in the end clear ! Either that or an air leak leaning it out. Use a tube to listen to all the joints and flanges and tubes.

    If the lack of a jet was the problem, it would rev up a bit and gradually cough and choke as the revs went up a bit. Blowing black smoke till it died. That,s my guess. jaahn

  11. #11
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    Default Jet !

    Hi Charger,
    I have located a few jets. Not a 92 unfortunately but I could "adjust" one to approximately that size and send it. It will work OK but will give you some time to find the correct one if you wish to do that.

    PM me your address if interested and I will do it Monday.

    Cleaning a carby means blowing out EVERY orifice and passage and jet in the carby so there is NOTHING blocking anything. I have "fixed" quite a few dirty carbys which had been "cleaned" previously by the owner and still did not work. Famous last words, 'But I already cleaned that'. Dave said some good words also.
    jaahn

  12. #12
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    Default My clymers book

    HANDBOOK OF IMPORTED CAR CARBURETORS AND FUEL INJECTION SAYS 28 IBT AS FITTED TO DAUPHINE HAS main jet 100 ,air correction 155k ,idle jet 45, choke jet 100, venturi 19, needle valve 1.5 and float 5.79 i will see if i can work out how to scan and send it to you, PUGS

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