As a side shoot I bought a 208 GT 4 at auction , it’s got 34 Webber’s not 40 s like the 308 . Then only thing in bold font was a A4 paper on the passenger seat with “ full choke do not press the accelerator after 20 seconds ignition “ In a smaller font “ If you depress the peddle it will not start “ Like the OP and after reading up about carbed 308s and listening to other owners all 3.0 L variants they waxed lyrical about zero choke ( even bragging its been taken out ) two pushes of the peddle and catch it method . I will tell you now that does not work and leads to flooding with the 34 s . Yes I have checked and do regular checks the choke turns off conscious you guys report they stick on with your 40 s . Cold = full coke no touching the peddle , and pick it up once it’s fired up and running .30 secs then take off the choke and let it breath out with a few low blips . Warm 1/2 choke , and catch it as it fires .It will not fire with no choke , just cranks over and eventually floods . Hot I mean oil temp up no choke needed . So when I drop it off at Ferrari specialist or normal mechanics I pull this A4 sheet out and leave it on the seat . Without cold choke it’s impossible to start .