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A car was towed to my shop that had been converted to webers and would barely run. After cleaning jets, synching carbs, setting timing car would idle fine and rev up when throttle opened by hand but has poor power and feels like a lean miss or erratic fuel mixture. I measured jetting, checked distributor advance, tried a 60 idle jet, no real change. Carbs are 40 dcoe 151, jets and venturies are correct for 2000 euro car. The manifold is fuel injection manifold with adapter plates. My question is should I be looking for correct manifold or spending more time tuning carbs. I would like to hear from people who have experience with the adapter plates. I have trouble believing that car would run this poorly when this setup is still being sold. Customer did buy this used and install it himself. I wish he had talked to me about the Spica before doing this. Thanks Will
 

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I would check for air leaks at the O rings in the adaptors. Also, special spring washers are used to maintain the correct pressure on the O rings. They can break if they are overtightened. This conversion can work well if it is installed properly. Also, make sure that the hole for the TA is blanked off on the manifold.
40DCOE151's are similar to the old 40DCOE32's and require similar jetting. You have some lattitude with idle jets. I expect 50F8 should work well.
Also, there is probably a fuel pressure regulator. It should be set at about 3 psi. A very low setting could give the symptoms that you are experiencing - so could a plugged fuel filter.
 

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I would check for air leaks at the O rings in the adaptors.......there is probably a fuel pressure regulator. It should be set at about 3 psi.
Did the car ever run well after the conversion? Or did the client bolt on the carbs, observe that it ran poorly, and immediately send it to your shop?

I'm with alfaparticle - an air leak or improper fuel pressure seem likely, particularly on an amateur installation. Those nylon plates with two O rings seem like a poor solution. The O rings swell from exposure to fuel, and don't fit neatly into the grooves.

Did your client install a fuel pressure regulator, or replace the Spica pump with a low pressure pump? Might too much fuel pressure be the issue?

A factory manifold certainly produces a cleaner solution for replacing Spica with Webers. The carb-manifold seal is better (assuming you use fresh vibration isolators), and the linkage is better. But, there's no reason why using adapters to connect Webers to a Spica manifold shouldn't function OK.
 
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