I have a 4 barrel factory Carter Carb on my 300 and it seems like the secondarys do not open or work correctly.I put her down heavy and I do not hear them kick in.They look like some sort of a crappy secondary setup to me anyway.I see there are weights in the secondarys and do not even understand how they work.I know on Rochesters you just push the throttle open and the secondarys move but this does not seem the way the Carters work.Someone please expalin to me how these damn Carters work.It seems like the Carters cannot even be opened when the car is not running.Rochesters open whether the car is running or not.Do the Carters use airflow to open up the secondarys?I have never been a fan of Carters but I guess I am stuck with it as I do not know a factory Carb that will swap with it.I do not want to go aftermarket as I do not think much of them.Any help on this subject appreciated.........Thanks
On the Carter, all 4 throttle blades pop open when you floor it. The valve you are seeing is a weighted air valve that opens as the engine needs the extra air...it weighted so you don't feel them open...smooth and gradual. It's actually a good system. As long as the lave is moving free and the secondary plates open (which they will unless the choke is on), you're good!
Thanks very much for the insight,I was expecting you would here them open as you do you in a Rochester for example,,,,,,,,Bruce.
:Smarty: The secondaries on the AFB and the Q-jet are actually very similar. Both have mechanically operated secondary throttle plates, with flow operated air valves above them. Airflow against the air valves works against a spring on the Q-jet, and the off-center weights in the AFB. The air valves are on the very top of the Q-jet, and down below the venturis on the AFB. The Q-jet has tiny primaries and HUGE secondaries. When those sewer pipes open, they create that beautiful sound we all know and love. Both have a mechanical lock-out to keep the secondary throttle plates from opening until the choke is fully open. If your choke doesn't fully open, or the lock-out tang is coked up with sludge, the secondaries may not be opening. The lock-out tang is on the driver side on your AFB. Give it a good spray with carb cleaner and make sure it moves freely and is completely disengaged when fully warmed up.
