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Weber IDF

Weber IDF is one of the best and most popular sports carburettors. Built by the Italian company Weber from Bologna. Currently, the company does not exist and its traditions are continued and developed by RedLine Weber from Spain.

(Side draft Weber DOCE was not mounted on 124 and 131 models due to too little space. They were used on front wheel drive models like Ritmo, where there was ample space.)

Barrel size is a matter of preference. Some will go for size 40, some for 44 and some for 48. No matter which one you want you have to have two different carbs: one left and one right.

Cold Start.

The original setup was with cold start (choke). Later the cold start setup became less popular due to problems it an cause. In these models the external cold start mechanism is not present ( just blanked off by a screw on plate).

In fact this is a half measure and does not cure the clogging problem. There is a set of jets beneath the blank off plate an they still do have a tendency to clog.

Some have chosen to totally block it off ( there is plenty of information in the internet how to do it. Some chose to fix it by applying the co called “Weber Jet Doctor”. Do benefits of easier start on cold outweigh problems it causes is a matter of individual preference and judgment.


Which Weber to buy ?

Unfortunately, the historic Fiat DOHC owners have a problem with currently produced Weber IDF’s : it is impossible to put two RedLine IDF Webers on the intake manifold for the a Fiat DOHC engine. Redline does not produce IDF pairs that can be mounted om a very tight Fiat DOHC intake manifold. They simply cannot be connected with levers to form a set of two double carburetors. There is not enough space ! Redesigning to make them fit requires precision mechanics skills, tools and lots of experience. Such reworked carbs can be bought to a ver significant premium, of you can afford it.

So the best bet is to get a used (complete) carb set from original Weber Bologna. Original Weber made four such dedicated sets , that fit on the Fiat DOHC intake manifold :

As Weber parts are widely available it is a very good option to follow.