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weber 40 DCOE problems

clive pritchard

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I have recently replaced the fuel injection on my 2.0 pinto with two weber DCOE 40 12s.

Its running horribly rich, and on tickover I can see fuel from one of the venturis dripping out.

I have rechecked the float level, and fitted a filter king reducing the pressure to about 2.5 lbs PSI to no avail.


Edited by clive pritchard
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Hi Clive,

Ran my pinto on 40s for years and they worked well once they were set up.  Here's a few thoughts -

Is it running rich on all 4 cylinders or just the one dripping fuel ?  Incorrect float level would normally affect both barrels of the carb. so 2 cylinders would be running rich.  Too high a fuel pressure can overcome the floats but that would probably then affect all 4 cylinders.

A couple of things to check :-

Have they been rebuilt and something missed out or fitted incorrectly ?

Are the jets somewhere in the right ballpark ?  I used to run 32mm chokes, 130 mains and 50f8 idles for the road IIRC.

Are the float bowls clean, filters intact and seals OK ?  It doesn't take much dirt to stop the float valve closing.

Is there anything restricting the airflow into the trumpets ?

I hope this helps, if I think of anything else I'll let you know.


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Many thanks Steve.

The jets are all pretty close to ideal, I intend to go to a rolling rd later to get them spot on, but having spoken with southern carbs I'm sure they are close enough to not be the problem. i got the carbs second hand, but had them ultrasonic cleaned, then fitted new gaskets, and new float valves. There are no resriction for the air. The weird thing is its just one barrel. I've double checked the float levels, and fitted a filter king, the pressure is below 3lb psi. Funny after a good clean, when i went back into the carbs I did find sediment in the bottom of the float chamber. It has a cold start, but Im sure those are firmly closed. Maybe take the carbs off again and blow everything through with an airline. Now the sun is out it would be nice to have it running! Thanks again.

Maybe i will switch the jets over and see if the problem moves, incase one of the jets has been messed with...


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It's not uncommon for jets to get drilled out bigger, if one is bigger you'll probably be able to see the difference if you hold them up to the light.  I once had a main jet stamped 115 which had been drilled out to 135 - confused the hell out of me for a few days !!

One other thing I thought of - are all the chokes the same size ? 

Good luck !


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