Weber Carbs Misting

[johnalfa1976]

I have a 1976 Alfa Spider. The SPICA unit failed. I converted it to dual Webers 40DCOE27 (used). I have put new gasket sets and needle valves on the carbs. When adjusting the sync, idle and mixture (Air Cleaner off - Engine at operating temp) accelerating the engine causes a fine mist of fuel to blow out of the venturies on both carbs and a small amount of fuel collects on the bottom of the venturies. I understand that the misting is typical of DCOEs but is it typical for fuel to collect on the venturies?

Thanks,
John

[papajam]

Welcome to the BB John!
The Weber 40 DCOE 27 carbs were originally fitted to the non-Veloce version 105 Series 1600cc engines so their 30mm venturies, 120 mains, 180 airs and 50F11 idle jets are just plain too small (assuming the jetting is original, of course). A 2l needs at least a 32mm venturi (34mm preferred), 130 mains, 210 airs and 55F17 idle jets. Although the jetting may be off, it shouldn't be the cause of the misting or pooling of fuel in the throats. Assuming the float levels are OK, my thought is that the cause is the cams. The original cams, 105.20.03.200.00, are designed for use with fuel injection, not carbs, and the 114 degree lobe center timing is more for low emissions than high performance. Re-timing the cams to 102 degree lobe centers will not only result a bit more engine power but should lessen the misting and pooling as well.

[kjp]

Try advancing the ignition timing a slight bit if you cannot get the carb hardware required. 34mm chokes definitely work, and 32mm should be fine too, 32 was the stock size on 2.0l cars.

It may be a good idea to take out your jets and chokes (can be done with carb still on the car) and find out exactly what you have since you bought them used.