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help with carb jets....

Discussion in 'Technical Q&A' started by smoothy, May 11, 2006.

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  1. smoothy

    smoothy Rookie

    May 11, 2006
    4
    #1 smoothy, May 11, 2006
    hi, i have a 1975 308 gt4 i have just found that i havedifferent jets in each carb! some one has fooled around with the set up and decided to have one carb with a 130 main jet and another with a 135 ect.... now wonder its runs lumpy! also the idle jets were different.
    At the moment iv replaced the jets and compromised to a 130 main,50 idle , f24 itube 220.

    do these sound ok? what are the correct jets lol...any help very much appreciated.
     
  2. miketuason

    miketuason F1 World Champ
    Owner Silver Subscribed

    Feb 24, 2006
    15,832
    Cerritos, CA.
    Full Name:
    Mike
    #2 miketuason, May 11, 2006
    You can start by checking your spark plugs for their color the one that has the Light brown/gray color is the one that has close to the right jet settings, this is just to get you in the ball park.

    Mike
     
  3. gerritv

    gerritv Formula 3

    Jun 18, 2001
    1,400
    St Catharines
    Full Name:
    Gerrit
    #3 gerritv, May 11, 2006
    Manuals are a good source of this information.
    Register your car at http://www.owners.ferrari.com. You can download an owners manual from there. The other manuals and tech bulletins are at http://dino308gt4.com
    Jetting is different for US and Euro cars. Also there are some differences depending on the altitude you use the car at.

    Gerrit
     
  4. smoothy

    smoothy Rookie

    May 11, 2006
    4
    #4 smoothy, May 12, 2006
    some interesting responses so far......thanx very much all.
     
  5. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
    79,406
    Houston, Texas
    Full Name:
    Bubba
    #5 BigTex, May 12, 2006
    Search this site..there is an informative chart of the various year 308s and what the factory jetting should be!

    Don;t worry one of mine came "all confused" like yours and returning it to fatcory specs and rebuilding the distributors had it as Enzo intended!

    I have it saved on another computer if no one will post it, I will later...

    Fchatter '91tr' has all that stuff,,,
     
  6. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
    Full Name:
    Phil Hughes
    #6 ferrarifixer, May 12, 2006
    Measure the jets first.

    You may find that although they're marked as a certain size, they've been drilled out to another..... This is quite common and quite ok, but "I" always grind off the mark to leave them blank if I do this.

    You need special drill bits or pick gauges.

    But it's easy to work out.... just in case you didn't know...

    130 is 1.30mm. 50 is 0.50mm 220 is 2.20mm etc etc etc

    The emulsion tubes I cant decifer. You need one of two types I think is all thats ever used.. F24 or F36.
     
  7. smoothy

    smoothy Rookie

    May 11, 2006
    4
    #7 smoothy, May 12, 2006

    thanx very much that would be help full.


    and thanx to all who have given there excellent advise much obliged
     

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