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Discussion Starter · #1 ·
Twin dcoe weber kit installed on a series 2 spider by previous owner. Looks like it was done right. Still has the electric fuel pump on it.
What should I be setting my fuel pressure regulator to? Was set at 3.5lbs when I bought it but not sure if that is correct.
Having stalling at red light issues.
Thanks
 

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3.5 psi sounds about right. You could take it up to 4 psi but my guess is that fuel pressure is not the reason for your stalling.

Where does the ignition advance settle after the car has been idling for awhile? The advance weights could be sticking, causing too high an idle speed when you first stop but then a stall when they finally settle against their stops.
 

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3.5 is correct, if its a speca conversion don't run it through the original fuel filter this will drop the pressure . 3.5 psi is not enought to push it through that large filter. Replace it with a standard inline filter.Also you don't need the return line to the tank so eliminate that open fuel source also.
 

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3.5 is correct, if its a speca conversion don't run it through the original fuel filter this will drop the pressure . 3.5 psi is not enough to push it through that large filter.
We don't know how Kenner's system is plumbed. I am assuming that the sequence is tank --> fuel pump --> fuel filter (either Spica or inline) --> regulator --> carburetors. So if the regulator is set for 3.5 psi, the carbs are getting 3.5.

But sure, if it's tank --> fuel pump --> regulator --> fuel filter (Spica) --> carburetors, the Spica filter could be reducing the pressure delivered to the carbs.
 

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I have my regulator set at 3.0 psi. 4.0 is definitely too high for my Webers.

But sure, if it's tank --> fuel pump --> regulator --> fuel filter (Spica) --> carburetors
Agreed.

Also get rid of the return line as suggested if you are running a low pressure pump. You will most likely need to keep it if you have the original Bosch high pressure pump as it requires continuous fuel flow for internal cooling.
 

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Discussion Starter · #6 ·
tank-pump-filter-regulator-carburetor
no vacuum advance.
I think it is the original HP pump. Loud.
there are filters in the carbs. Should I be checking them?
 

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there are filters in the carbs. Should I be checking them?
Before you do that, why don't you tell us more about this "stalling at red light issue". Does it happen as soon as you take your foot off the gas or will it idle OK for awhile, and then die?

If the former, then tune the Webers including the four idle mixture screws.

If the latter, then I still think it is ignition, rather than fuel pressure or filters in the carbs.
 

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Discussion Starter · #8 ·
1)car will idle normally around 900rpm. rev and release and it will sometimes drop to 6-700rpm and stall.
2)car will also idle at 900, depress the clutch and it is enough to drop the rpm to around 6-700rpm and it stalls.

3)also sitting running in my drive way it will act normal, again idling around 900rpm then it will stumble and drop to 6-700 and either recover or stall. this will repeat in about 1min intervals
 

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Are the Webers the standard 40 mm or the lager 45 mm?
If the engine is in standard trim the 45 mm Webers will have a slower air speed at the venturis than intended.
However, my standard 1750 Weber engine also have a tendency to idle at lower rpm (about 700/800) after a minute or so, but seldom stalls '(only when not at running temp.) When hot idle rpm are 1000'ish.
 

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They are 40's. It is unusual to have a mixed pair but they may be the same internally. Gordon Raymond will know for sure. Are you confident that they are properly synchronized?
 

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Discussion Starter · #12 ·
Pretty confident the conversion was done properly. Believe it was done at Maranello in Woodbridge. P.O spared no expense when it came to parts and service for the car so I am guessing it was done right.
 

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The "32" and "28" denotes the diameter on the venturi inserts and they are changeable, so the are probably both 32, which are the correct for 1750 & 2000 engines.
The nozzles are different for 1750 and 2000s.
 

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The "32" and "28" denotes the diameter on the venturi inserts
That is incorrect. The last two or three digits denote for which car they were original equipment. 40DCOE28 was OE on the 1300 GT Junior and 40DCOE32 was OE on 1750's.
 

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I'm sure that there are Weber specialist in the US who knows which parts that are suited for each engine. All I say is, that Tanner's two Webers have different numbers (28 and 36). Probably the venturi are the same but that doesn't mean that all jets in them are correct for his engine. If they are and the carbs are sett up correctly its something else that causes his engine to stall. Like ignition or what have we. An trained/experienced Weber and Alfa technician will soon diagnose the problems, what ever is the matter.
 

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P.O spared no expense when it came to parts and service for the car so I am guessing it was done right.

Double check you never know
start simple ,a small air leak, a misaligned o ring gasket, if a euro intake manifold does it have a support bracket,on US its not necessary.
Webers are cool carbs and run well but when they decide to do weird things they can be a bear to troubleshoot.
The problem may not even be the carbs ,since you had them redone the problem may now be someplace else and is just now showing up.
Just guessing at this point Let us know what you find.we all learn.
 

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If the pair of carbs aren't supported the rubber gaskets between cylinder head and carbs can go loose or crack. 2 double carbs and air filter have some weigh and needs the support rod whether in the US or elsewhere.
But right, it could be lots of things that causes the stalling.
 

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a small air leak, a misaligned o ring gasket, if a euro intake manifold does it have a support bracket,on US its not necessary.
keymastr1 raises a good point here. How was the Weber conversion done by that P.O who "spared no expense when it came to parts"?

- Did he cheap out and just use adapter plates on his existing Spica manifold (which is what I think keymastr1 meant by "US", since Spica was primarily a US thing)? In my experience, that set-up is more prone to air leaks which could be the cause of the erratic idle.

- Or was the conversion done with a factory Weber manifold? The flexible carb mounts used with the factory manifold are more substantial, less prone to air leakage. However, those mounts can crack with age, creating air leaks. And a support rod is required with these manifolds.

So Kenner: how was your conversion done? Can you post any photos of it?
 
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