Fast Idle | FerrariChat

Fast Idle

Discussion in 'Technical Q&A' started by drivemycar, Oct 9, 2020.

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  1. drivemycar

    drivemycar Rookie

    May 24, 2016
    14
    I have a '79 308 and I am working on my carbs with the help of Birdman's tutorial and all the relevant threads I could find. I haven't seen any that reference the fast idle adjustment driven by the thermostatic spiral and attached cam. Mine has been disengaged for about 35 years now and I wonder why. I have the all too familiar idling fluctuations and it seems that this secondary throttle adjustment might help during warmup. Does anybody have an opinion on this?
     
  2. mwr4440

    mwr4440 Five Time F1 World Champ
    Rossa Subscribed

    Jun 8, 2007
    55,828
    Bavaria, The 'Other' Germany
    Full Name:
    Mark W.R.
    If you are talking about the 'Fast Idlewild at Warm-Up,

    WHY would you do ALL THAT Wear-n-Tear to a COLD Engine?


    Ferrari created that wholly DESTRUCTIVE 'Feature' merely to warm-up the cats faster for CALI Emissions Standards at the time.
     
  3. drivemycar

    drivemycar Rookie

    May 24, 2016
    14
    I think we are talking about the same "fast Idle Device" found on page O4 in the workshop manual. While it appears in the manual as an emission control device, the cats, air pump, and all are also gone about 35 years. I set the the rocker arm at the cam position 20 for the moment on a cold engine. I set the idle stop screw on the rocker arm to idle cold at 1000rpm.When the engine warms to about 185f the rocker arm collapses at the cam and the throttle stops on the carburetors take over. I was using the choke to warm up the engine, but this seems much cleaner, effectively an automatic choke but not. I haven't been able to find much about this and keep thinking I must be missing something, but it seems to actually work the way I expected it to. It's not the result I usually get.
     

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