It's a CCC 4-Brrl, and it seems like the car has the infamous quadra-bog, that is to say, I have what I can best describe as a "flat spot" between when the primaries are open wide, and the secondaries start opening. It almost seems like the secondaries open up too late. It's not the original L69 carb. It's a rebuilt Autozone carb, so, I found out later that I gave the good hangers and rods in my L69 carb back to Autozone as a core.


Anyways, how do I get rid of this? I think it runs awesome for a 305, but this problem persists. Any help appreciated.

BTW, I set my timing around 10 degrees advanced, and it seems to run great there. If advanced more, I can't get it started.

 

check this tech articles on tuning the CC quad jet. https://www.thirdgen.org/newdesign/tech/quadrajet.shtml

 

That's usually caused by the air valve opening too early, not too late. If they opened too late, the car would run like it was a 2-barrel: i'e' you'd never even notice that you had opened the sec throttles.

Tighten the air valve spring to about 5/8 turn of tension, that is where mine seems to work best.

 

I had the same exact problem, my carb is an Autozone replacement too. On mine they had CH rods with a K hanger in there; very bad setup for an L69.
Also, they gave me a bad TPS and a really lean primary mixture adjustment--might wanna check those two items as well.
You'll want to get a hold of the DR rods and a G hanger if you want the stock L69 setup, or substitute a B hanger if you want a little more kick on the transition. You might have to re-tweak the air door tension when you put in the new rods & hangers. Gotta love Autozone sometimes.

 

I appreciate all the responses! - RB, I'll try adjusting the spring tension on the air valve. That might explain why I get a puff of black smoke when I push it hard.


eightTfourTA - Glad to hear I wasn't the only one this happened to!! I definitley want to get at least the stock hangers. Know of a good source? Part numbers maybe?

 

I got the hanger from www.carbsunlimited.com. The rods came from www.gmpartsdirect.com. The GM part # for DR rods is 17053659. You might be able to get them thru a local dealer, but my experiences with the dealers here have turned me toward the internet for stuff for thirdgen cars (the order screen doesn't try to sell me a used '94 V6 Firebird for 12K!! )

 

Black smoke is an indication of unburned fuel, or a rich condition. It might also be your engine kicking out some carbon buildup if it has really gotten bad

 

Sitting Bull - I totally agree with you, but it's not a constant black smoke.... only when I tromp in it. Besides, the engine only has about 500 miles on it since the rebuild.....not enough time for any carbon build-up. And of the 500 miles, the first 300 of them was normal driving...I didn't wind it for "break-in" purposes. Since then, I don't hesitate to open it up!

I was ALMOST going to just swap the whole engine and get a 350....and in some cases it makes good sense, but I don't regret rebuilding my 305 for a second. I've owned slower 350's in the past.

I think when I finally swap up, it will be a 454 or 455 big block.
In my opinion, the stump-pulling, low end torque of a big block is the way to go!

eightTfourTA: Thanks alot for the info!!

I'll just install the hanger and rods first, then adjust the air valve as RB mentioned, so I don't end up tweaking it in twice. They should be pretty inexpensive right?

- Doesn't matter anyways, cause when you're in as deep as I am into this car, it's all just chump change.