Adjusting idle on 365 GTC/4 | FerrariChat

Adjusting idle on 365 GTC/4

Discussion in 'Technical Q&A' started by rgdelagi, May 21, 2023.

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  1. rgdelagi

    rgdelagi Rookie

    Mar 17, 2023
    9
    Full Name:
    Greg Delagi
    I just had my car serviced (owned it a couple of months and have put ~300 miles on it). It was running great until I transported it half way across the US for the summer. When the transport company tried to pull it out of the truck, it kept stalling. I can keep it running by applying a little more throttle so it seems I need to adjust the idle up a little. This is complex with the 6 carbs... can someone help me with how to do this since I am 1800 miles from my mechanic?
     
  2. wmuno

    wmuno Formula Junior
    Silver Subscribed

    Dec 24, 2007
    522
    Wilmette, Illinois
    Full Name:
    Bill Muno
    There are 2 rods with jam nuts that control the throttle plates on each bank. See #19 in the atatched diagram. Loosen the 4 jam nuts and turn each rod the same amount to increase the idle speed. Tighten the jam nuts when finished with the adjustment. Caution - it's important to turn each rod the same amount to maintain the synchronization of the two banks.

    https://ferrarispares.com/allferrariparts/afptimages/tbl14541.jpg
     
  3. rgdelagi

    rgdelagi Rookie

    Mar 17, 2023
    9
    Full Name:
    Greg Delagi
    Thank you so much WMUNO! Everything seems fine if I just give it a couple hundred RPMs with my finger. Mechanic set it for 1000-1050 and it seems like it is running at 5-600. I can’t figure out how this happened in transport. I’ll give it a try.
     
  4. Island Guy

    Island Guy Karting

    Feb 20, 2020
    139
    Full Name:
    Island Guy
    Before you touch any mechanical linkage, which will not change all by itself (unless not properly tightened), it would make more sense to inspect the carb idle jets for debris/blockage that will affect idle quality/speed. And a call to your mechanic would be prudent as starting with the linkage is not the best path....
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Before doing anything mechanical adjustment-wise, make sure that you have ignition spark on both banks (and aren't running on just one bank). All of the Ferrari 2-bank engines run very smoothly on one bank but at lower idle RPM (and would have less power), and your symptom matches that well (and your model has near-completely separate ignition systems for each bank).
     
  6. Zanny1

    Zanny1 Formula 3
    Silver Subscribed

    Dec 19, 2003
    1,161
    Arizona
    Full Name:
    Mike
    Ditto what Steve says. Don't mess with any carb settings until you are sure the motor is running on all cylinders.
    You don't mention if it a euro (one distributor) or USA (two distributor) version.
    Hot idle on my C/4 is 1200 RPM. You can adjust the butterfly setting on each carburetor, which will change the idle speed, by turning each idle stop screw CW an equal amount. Having said that, other aspects come into play, such as idle mixture settings.
    Make sure the motor's running on all cylinders and get back to us.
     

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