So, i started the disassembly of the CCC from my '85 LG4 'bird. the carb was a reman some time ago, perhaps 20 years based on the sticker. dunno.
Anyway, when i pulled off the airhorn two of the tubes were found to have fallen out at some point. They were just lyin' there. I'm not exactly sure what the tubes are but I believe one is for the idle circuit and the other a fuel feed tube for the secondary circuit.

Its a bit difficult to tell what they do, even with my Doug Roe book. the GM manuals don't even show the tubes in the expanded diagrams. from the book the early non-CCC carbs both pair of tubes appear to be for the secondary circuit. but on CCC one one pair is for idle and the other for secondary.

-Is there a clear explanation of what the function is for each pair of tubes?
- what characteristics will I experience/notice with one, each, of these tubes having fallen out? idle issues, secondary performance etc
- will the idle tube cause an extremely rich condition? or will it be extremely lean due to no fuel?
-the secondary I would imagine would be way down on power.

I've only had the car for 1.5 weeks. It ran terrible. about half, yes half, of the vacuum tubes were disintegrated and the other half plugged with bolts. The evap system plastics were also badly broken. I fixed all the necessary vacuum (EGR, accessory, brake, etc) and capped the rest (EFE, evap, etc). I also spent quite a bit of time resetting timing, and curb idle. I started on the IAB & DWELL before my 25yr old meter took a dump.

The car idles badly, really rough. the mixture solenoid clicks away as normal (I have an L69 Monte too). the exhaust is eye watering rich at idle. It isnt' bad at cruise, fairly smooth with no major hesitations etc. There are alot of other things wrong with the car too though.

I went ahead and pulled the carb to rebuild and found the tubes fallen out as well as badly corroded well plugs, loose screws, you name it. the primary throttle shaft is a tad loose, but it has been rebush'ed before. I think I'll skip that for now. I don't want to put any more money in this core. it is really rough. I'll get another if I do it over again later. parts kits are cheap and I have the tools already.

see pic, two are still in place. on is laid over. the 4th is down in the well somewhere.

look at those venturies. they are BEAT. looks like someone put them in a rock tumbler.

anyway, those tubes? Just to be clear, I'm fairly certain they had fallen out long before I started disassembly.

 

The set with the tapered ends is the secondary air bleed. Adds air to help emulsify the fuel. The larger ones are a sort of "accelerator pump" for the secondaries; they provide a small shot of extra fuel as the blades open just past the little orifice at the top of them, which is about 1/8" or so above where the blades sit when at rest. As the blades open they expose the orifices to whatever manifold vacuum happens to exist at the moment, drawing out a bit of fuel, to reduce the secondary "bog".

They fall out ALOT. Very common. They also often get bent by various rough handling.

Neither one will affect idle. With the air bleed one missing, that side of the secondaries will be rich and the fuel reaching the sec venturis will be a liquid instead of a foam as it's supposed to be. The other tube missing will affect secondary tip-in (the "bog" may return).

The primary venturis get like that often during unskilled labor. They are slightly above the level of the flat surface of the carb, therefore when the fuel bowl is set on a surface upside-down, those are supporting its weight. Looks like whoever dinked with it, was very careless in handling it. Amateurish at best. AFAIK it doesn't affect operation too much; just, will carry the evidence of the ham-fisted HACK with it to its grave.

The burn-your-eyes idle is probably from the well plugs. Loose screws sounds like further evidence of dissimilar-metal electrolysis; eroded threads in the castings. Probably not worth saving, but if necessary, those things can be repaired; Heli-Coils for the threads, epoxy for the well plugs and those secondary tubes, etc.

 

yeah, thanks.
I read on another post (the other day) about the well plugs and over rich idle.
I've done the CCC on my Monte not too long ago, but that one was solid and worked out really well other than a bad choke thermostat & accelerator pump. It was all original and never monkeyed with.
I was planning on epoxy on the well plugs and the tubes tonight or tomorrow. everything else will go back together soon. If I find anything stripped I may use green locktite...
i don't plan on redoing this one again, just this one time to see 'if I can revive it'. so, it likely won't ever come back apart again.

My 'new' replacement 20yr old dwell meter should arrive friday. so hopefully i'll have it dialed in then.

 

Here is where the confusion comes from.
both pics are from Doug Roe's book.
First is from the non-CCC carb section showing the four tubes, all indicating secondary functions.
Second is from the CCC section where the labels show the small tubes are idle tubes. However, i don't see TPS or MCS components in that pic either so its an earlier carb.

 

No. No! NO!! NO!!! NO!!!!!!!!!

Heli-Coil.

There are few things worse than standing over a mess with recessed Phillips drive screw heads, realizing something (hardly matters what) went wrong, and NOW... you're FORNICATED.

Heli-Coil.

12-24 in some places and 10-24 in others if memory serves. Don't take my word for it though, CHECK by using a thread gauge.

The needle & seat is 3/8"-24. YES, I've had to Heli-Coil those before, when the electrolysis was SO BAD, fuel got around the threads.

ABOVE ALL, don't EVER hallucinate that this is "the last time evah" that you'll have to touch this. If your luck is anything like mine, then what will happen is, you'll Heli-Coil it, and everything will go together perfect and you won't EVER have to disturb it again and you'll feel like an idiot for spending all that money on the Heli-Coil kit(s); but if you Loctite it, you'll have to tear it back down AT LEAST twice afterwards, and deal with stripped Phillips drives, broken-off screws that are too short to get a vise-grip on, cracked castings from trying to bull your way through, and on and on.

After all, Murphy was an optimist. People quote what THEY THINK is his law; but in reality, The Law is, "whatever can go wrong already has, and you just won't find out about it until it's too late to do anything about it. And then, when you finally DO find out and you're accidentally still alive and you do try to do something about it, whatever you did before, will oppose you with all its might."

Live and learn. Or you don't live long.

Incidentally the 1st pic's caption is correct. And, only 66-back carbs have the fuel-based damper piston (A). You don't have that.