repeat emissions fail for HC (hydrocarbons)

[rigel]

after the first failure (2x limit, 3x after rev) i got a rebuild kit from napa and rebuilt it.

now the carb is leaking fuel from somewhere right above the accelerator pump. it increases (obvious dripping) when the accelerator pump gets used. took it (the accelerator pump) apart again, tightened the crap out of it, still leaking. just a drip-drip-drip but i suspect its related to:

a second failure with even higher HC levels.

i have tried to use a mirror to pinpoint the source but still havent been able to find the exact source. it seems like one of the check valves is right there?

i've turned the idle mixture screw all the way in, because turning it right made it idle lower. it bottomed out right about where it starts to misfire.

is that the right way to try and lean the mixture?

[2oodoor]

The actual idle mixture screw, which should be rather large, should never be screwed all the way in. As an industry wide standard most of the time those are like 1.5 to 2 turns out.
Is the carb leaking externally or internally, I wasnt clear on that.
It is ordinary for carbs to have to be taken apart a couple of times to get everything just right on assembly, especially if this is the first one of this type you have done.
For what its worth (FWIW) I will now give you my generic answer to these type questions... WEBER! you should be able to pass emissions with a 32/36 Weber if you tune it carefully and make sure the engines vac advance is working properly. In Cali, you would have to fabricate a OEM factory air cleaner to work with the Weber. Things need to look original: This could be done by cutting the bottom cleaner carb flange mate and MIG welding the Weber air cleaner flange in there... havn't seen anybody do that but it is doo-able in sure :)

[rigel]

sorry, i'm not talking about the idle mixture screw (the big black plastic one) but about the a/f mixture screw that's recessed behind the mounting plate on the firewall side, and has the little insert to prevent you from messing with it. it was about three turns out and didnt look like i had been messed with (had the little insert in it) but i just need to lean it out enough to pass emissions, and i couldnt figure out how else to.

i'm considering a weber, because it's not much more expensive than a reman carb from national. i really do not want to go down a fabrication rabbit hole right now though, especially just for an emissions fail.

as for the leak, i'm not exactly sure where it's coming from either. it's dripping onto the top of the accelerator pump diaphragm, but to the rear (engine-wise, i.e. towards the passenger side) of the accelerator pump linkage so both the linkage and the "top hat" prevent me from seeing the source all that clearly.

[rigel]

so, passed emissions today with less than half the max HC.
i brought the idle up to about 1100 with the black knob, turned the a/f mixture all the way in (as noted above) and drove it a good 20 miles before taking it to be tested. my reasoning was that i wanted to lean out the mixture with the a/f screw and bring the idle up so that it was using more of the gas it was obviously getting somehow anyway.

i probably will not get a weber now, but maybe on the next 3gee...

the fuel drip is still there, and it bothers me. not good for MPGs...

[Dr_Snooz]

Why don't you fix the leak so the car runs properly?

[rigel]

i'd like to, but i cant even figure out where it's coming from let alone how to fix it.

SUGGESTIONS WELCOME