Any Weber experts here?

[thorsen]

I installed a set of used Weber 32/36 DGEV on my 1972 250C and I am having a problem with one of the carbs. The front carb looks like it is working fine, but on the rear carb, fuel is pouring out of the auxiliary venturi when the engine is running.

Before installing the carbs, I rebuild them - new accelerator pump and gaskets.

I eliminated float height as a problem (removed the top cover and ran it but still had problems) and ruled out the power valve (with the top removed I activated it with a screwdriver).

The choke is not the issue - on both carbs the covers open at about the same rate.

I made sure the main jets, emulsion tubes, and air corrector jets were clean and open, but I am at a lost as to what to do next. ?Any suggestions would be appreciated.

[thorsen]

Also, I screwed the idle jet all the way in and no change.

[thorsen]

I swapped the main jet, air jet, and emulsion tube between the two carbs, and the rear carb is still leaking. I think the carb has problems.

[Chas H]

Are the carbs balanced for air flow?

[Blue 72 250]

sounds like a balance issue to me. One carb is "pulling" the other.

[thorsen]

I'll pull out my unisyn and check.

I am familiar with tuning the dual SU's on my MGB - I assume the procedure is the same? Adjust the idle speed screw so they both pull the same?

[thorsen]

I think I figured it out falling asleep last night. The vacuum port for the seat locks is located on the rear of the intake manifold, and since I don't have any seats (or interior for that matter) in the car right now, what I basically have is a huge vacuum leak.

I will plug that port off tonight and see if it improves any.

[thorsen]

Plugged the port and both carbs behaved normally. I checked them with the Unisyn and they are both in sync.