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Well I could never find what was causing my Dellorto DHLA carb to suddenly cause cylinder #4 run so rich. After much cleaning and inspection I finally decided there must be a crack somewhere in the body causing fuel to leak into the idle circuit. So I ditched the Dellortos and purchased a (modern) pair of Weber DCOE 40 carbs. I set up the Webers using the values on the Centerline website (https://www.centerlinealfa.com/sites/centerlinealfa.com/assets/files/default/weber_jet.pdf)
My 1972 Giulia is a 2 liter with a Eurocam and I live at 6,500’ elevation. I decided to start with Centerline’s sea level jet suggestions because I found in the past that sea level values still work pretty well in my other cars. It’s likely all the ethanol in our fuel here affects the traditional altitude adjustments anyway.
The Webers provided noticeable better performance than my fifty year old Dellortos. I’m very happy… except for one thing. I have a VERY noticeable flat spot when I open the throttles. Because it occurs at all speeds and rpms I think it points to an issue with the acceleration circuit.
Centerline recommended a numerically smaller pump jet (35 vs 40) and a numerically larger (60 vs 50) pump exhaust valve than what came with the standard Weber setup. My first question is does “numerically” translate into physically larger. I would think so but just want to make sure. If this is the case then the Centerline values mean considerably less fuel going in than the manufacturers shipping configuration. Second how do the pump jet and pump exhaust valve interact to determine how much fuel is being provided to the engine? Finally, if there is anyone out there using Weber DCOEs on their 2 liter would you let me know what jetting values you are using?
Thanks, Phil
My 1972 Giulia is a 2 liter with a Eurocam and I live at 6,500’ elevation. I decided to start with Centerline’s sea level jet suggestions because I found in the past that sea level values still work pretty well in my other cars. It’s likely all the ethanol in our fuel here affects the traditional altitude adjustments anyway.
The Webers provided noticeable better performance than my fifty year old Dellortos. I’m very happy… except for one thing. I have a VERY noticeable flat spot when I open the throttles. Because it occurs at all speeds and rpms I think it points to an issue with the acceleration circuit.
Centerline recommended a numerically smaller pump jet (35 vs 40) and a numerically larger (60 vs 50) pump exhaust valve than what came with the standard Weber setup. My first question is does “numerically” translate into physically larger. I would think so but just want to make sure. If this is the case then the Centerline values mean considerably less fuel going in than the manufacturers shipping configuration. Second how do the pump jet and pump exhaust valve interact to determine how much fuel is being provided to the engine? Finally, if there is anyone out there using Weber DCOEs on their 2 liter would you let me know what jetting values you are using?
Thanks, Phil