Carb teardown, one cylinder had black stuff in it

[berettafan]

This is probably a very simple question for the experts.....

When i removed my webers for rebuild i noticed one velocity stack had more dark brown 'varnish' on it than the others. "Hmmmm" i thought to myself. (I know, brilliant huh?)

Then upon teardown of the carb i noticed the same venturi had black 'staining' whereas the others were surprisingly clean (carbs themselves were filthy). I further noted the secondary ventury also had black 'staining' on them as well. Other secondary venturies are clean.

And the last piece of the puzzle is the intake manifold had a crack at the base by the bolt hole, as if it were overtightened. I think this crack was at the base of the runner which corresponded to the carb throat in question. I am not POSITIVE of this as i have already sent the runner out for welding and the relationship hadn't occured to me yet.

Erik


Oh, some interesting other info on the carbs;
-the needle valves on both carbs had anywhere from 2 to 5 washers on them. my guess was when tuning them the wrench didn't feel like (or PO didn't want to pay for..) pulling the carbs to tweak the float tabs.

-i pulled the carbs for rebuild because there was obvious weeping everywhere and the car had a backfire at idle. also heard evidence of what is commonly described as a 'pfft' sound that i have heard diagnosed as a leak somewhere. the base of the other carb had a very obvious leak where it met the spacer on the head (not the carb/head in question).

-Motor is a 2.4T case reportedly rebuilt with S cams and 2.2S pistons. In looking at the intake ports it is clear that they were opened up to some degree. have yet to get a good measurement of intake diameter because i haven't gotten the nerve to pull the spacers off the heads (studs are a bit corroded and i don't want that nastiness falling into the intake).