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Weird mod on carb covers

Discussion in '206/246' started by stanzeman, May 15, 2010.

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  1. stanzeman

    stanzeman Rookie

    Sep 25, 2006
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    #1 stanzeman, May 15, 2010
    Last edited by a moderator: Sep 7, 2017
    Hello. While cleaning the carbs, I realised all 3 carb covers seem to have been modified. There is a hole which has been drilled. It looks like a "vent" for the float chamber. Can anybody tell me if this is original or a modification. Thanks
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  2. dignini

    dignini Formula 3

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    #2 dignini, May 17, 2010
    The car ran like this?
     
  3. stanzeman

    stanzeman Rookie

    Sep 25, 2006
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    #3 stanzeman, May 18, 2010
    Yes it does but the plugs would get dark really quickly. I thought it was a float height problem but I am now thinking that gasoline is drippng in the carb from these holes...
     
  4. DinoLasse

    DinoLasse Formula Junior
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    #4 DinoLasse, May 19, 2010
    Last edited: May 19, 2010
    Do you suppose it could be a misguided attempt to cure the well known fuel starvation on sharp left turns? I know that many have tried to cure that problem, without success. I also understand that the fuel level in the float chamber is critical in order to minimize the starvation. From the photo I can not quite picture under which condition that notch would come into play, so I am just guessing about the intention of the modification. Anyway, just a thought.
     
  5. stanzeman

    stanzeman Rookie

    Sep 25, 2006
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    #5 stanzeman, Jun 14, 2010
    Last edited by a moderator: Sep 7, 2017
    Hello. I have now plugged these holes but I made things worse! The carbs get flooded the second the fuel pump is on. I guess some air pressure is building up in the float bowl chamber that pushes the fuel down through the main jets. I looked for carb cover pictures on the web and came accross this one (In Japan I guess) and I can see the same vent on this one.
    So back to my original question, should there be a vent on the carb cover or not?
    Can anyone be kind enough to go check on their car if they can see the same perforation on the carb cover? Thanks!
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  6. swift53

    swift53 F1 Veteran
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    #6 swift53, Jun 14, 2010
    Mine have it. Regards, Alberto
     
  7. stanzeman

    stanzeman Rookie

    Sep 25, 2006
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    #7 stanzeman, Jun 14, 2010
    Just done further research on the subject and it seems that all Weber carbs have this vent so the float bowl does not get pressurized by the fuel pump. I need to look somewhere else for solving the running rich problem. Thanks for the support.
    Stan
     
  8. dm_n_stuff

    dm_n_stuff Four Time F1 World Champ
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    #8 dm_n_stuff, Jun 14, 2010
    Are/were all the notches identical on the carbs?

    IF not, I'm wondering if it's some kind of factory fine tuning that was done by hand to get proper float levels or vacuum readings or whatever.

    If they were IDENTICAL, then they were cast that way and should be left alone.

    D
     
  9. celestialcoop

    celestialcoop Formula Junior
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    #9 celestialcoop, Jun 14, 2010
    Last edited: Jun 14, 2010
    On page 177 of the the Haynes Weber book, there is a picture of a cover with a notch similar to, but larger than, yours. I scanned the page, but it exceeds the file size limit & I don't know how to compress it. At any rate, it's there...no verbiage in the book as to size, shape or function of the notch.
    I've had nine of these DCNFs apart (a mere novice :)); I don't recall even noticing the notch.
    Coop
     

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