Author Topic: Fiat 903cc Carburation  (Read 913 times)

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Offline Sean Zahra

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Fiat 903cc Carburation
« on: February 14, 2022, 10:41:30 pm »
Hi, I'm relatively new to this forum. I have a fiat 850 sport coupe with a 100GBC engine. The engine currently is bored to 65.6mm making it 919cc with the sport type higher compression pistons. Modifications include a 296 degree camshaft, slightly ported head and a weber 36 DCD3. The car is hesitant between the 3700 to 4700 rpm range when full throttle is given and I'm blaming the carburettor. Other than that the car drives very smooth and up until this hesitation accept full throttle and after this hesitation it acceptable full throttle again. During the hesitation I need to let go slightly off the throttle. Any recommendations to what the jettings shoul be similar to ? Currently running on 25mm chokes. Should I decrease these to 23mm ?


Offline Pantdino

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Re: Fiat 903cc Carburation
« Reply #1 on: March 21, 2022, 03:33:14 am »
Pierce Manifolds in California is a Weber specialist and can suggest jetting based on your description of the engine.  Great source of help and parts.