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Does your carb 308 experience hesitation or stumbling in the corners?

Discussion in 'Technical Q&A' started by Mike328, Jan 30, 2004.

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Does your carb 308 experience hesitation or stumbling in the corners?

  1. No, and the car never did

  2. No, but the car used to (specify fix)

  3. Yes, at slow/street speeds only

  4. Yes, at the track only

  5. Yes, at both slow speeds and at the track

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  1. Mike328

    Mike328 F1 Rookie
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    Oct 19, 2002
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    Mike
    A thread was recently posted on FerrariChat about a 308 loading up in the corners (which could be loading up or fuel loss, not sure):

    http://ferrarichat.com/forum/showthread.php?p=101060#post101060


    In a thread in June of last year, I counted six of us who chimed in with the problem:
    http://www.ferrarichat.com/discus/messages/256120/262013.html?1055302715

    Some indicate that it happens at low speeds, others that it happens only on the track. There is a definite trend of people who have the problems at low speeds...

    I just had my carbs rebuilt, and have them reinstalled, but have not yet had the car out to test if the rebuilt fixed the problem. I'll report back when I take 'er out.

    Let's get a feel if anybody other carb 308 owners have the problem... Non carb 308 owners need not apply :).

    --Mike
     
  2. Mike328

    Mike328 F1 Rookie
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    Also, if you vote "yes," why don't you post a quick note to the thread so we know who you are... We might be better able to resolve the problem this way, assuming there is a solution.

    Yes!
     
  3. juanito308

    juanito308 Karting

    Mar 7, 2003
    93
    Littleton, Colorado
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    John
    I have a '79 GTB with a Euro Ansa catless exhaust. When I bought the car 18 months ago, it had the belt on the air pump and the carbs were set pretty lean. Since then I have removed the pump belt and richened the mixture (only after passing Colorado's draconian emissions test). The car now has collector plates (>25 years old) so hopefully I won't have to go through emissions anymore.

    Anyway, when the car was lean and the pump was turning the car seemed to cough at slow speeds on twisty roads. One way around that I discovered was to keep the rpm's up, doing more heel and toe shifting (not that I am any kind of racer whatsoever), but it seemed to help. After the car was tuned post emissions, i.e. richer, the problem remains only not as severe. It seems to me then that the carbs are becoming fuel starved on hard turns. By keeping the fuel flow up and the intake drawing, my car seems somewhat more responsive.

    Just some observations from a non automotive engineer/mechanic albeit enthusiast.
     
  4. Dom

    Dom F1 Veteran
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    Nov 5, 2002
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    Dom V.
    Yep, I get some hesitation in corners. Also, when I stomp on the gas pedal from a stop, it will hesitate just ever so slightly. I've always assumed it was the nature of carbs.

    Dom
     
  5. Mike328

    Mike328 F1 Rookie
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    Dom, I'm pretty sure those two are different symptoms which related to different problems, although it's possible the two problems are related.

    Hesitation on any kind of acceleration could point to a progression hole/throttle plate position problem, or a accelerate pump (system or just jet) problem, or other jet problem...

    This other corner-hesitation problem is a bit different, I think.
     
  6. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
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    Hans E. Hansen
    Slight stumble/misfire at small throttle openings. Like about where the progression holes would be. Open the throttle just a bit and all is fine. Open more, and YEHAA!!!
     
  7. Peter

    Peter F1 Veteran
    Owner

    Dec 21, 2000
    6,387
    B.C., Canada
    Nope, never did.

    Only hesitation was once during pulling away from stops... Big time. P.O. mechanic installed way too small idles (45's). Popped in correct 55's, no problems. Searching for more power, threw in 60's, but bogged the car down too much (very slow to accelerate). Back to 55's and staying there.
     
  8. Mike328

    Mike328 F1 Rookie
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    Well, I've got my carbs from Pierce Manifolds back on and synced up. Just took the car for a test drive... Still have the fuel starvation in slow speed corners.

    I don't think this is related to float level; mine are set right on, 48mm and 58.5mm...

    It's possible it's a timing issue, so it would be interesting to see whether or people who experience this are using an aftermarket electronic ignition (Electromotive, Pentronix, Crane, Millermon, MSD, etc.). I'll be installing an electromotive shortly so will know more then.
     

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