How to de-bog your Quadrajet part 2
The Rochester Quadrajet has gotten a bad rap over the years, but it's
actually an excellent carburetor once you understand how they work.
Often referred to as "Quadrabog" or "Quadrajunk", many of the issues these
units suffer stem from neglect, or "modifications" that do more harm than
Being a spreadbore, air-valve secondary design, the Quadrajet is capable
of flowing 750 or 800 cfm of airflow, eliminating the need to buy different
carburetors when your set-up changes. In addition, the small primaries make
for great drivability and fuel economy.
In this clip, I'll discuss theory of operation on the secondary side,
since that's where most problems arise. So, leave your preconceived notions
at the door and let's see what makes these carburetors tick.
750 vs. 800cfm Rochester Quadrajets-how to tell them apart
There exists a ton of misinformation regarding the actual airflow capacity
of the Rochester Quadrajet. Not many people know how many variations there
are or how to tell them apart.
Here is a simple video explaining how to identify each size based on
casting design. I will cover the "cfm-limited" carbs in a separate video.
Decoding a Rochester Quadrajet part 1: The name
Rochester Quadrajets tend to mystify people because of the various model
names assigned to them by GM.
Add to that a redesign in the '70s and the confusion only grows.
In this video we'll learn the different model names and also how to
differentiate between early and later-model Qjets. Enjoy!
How to adjust Quadrajet/Dualjet fast idle
Quadrajet/Dualjet Rochesters have a fast idle adjustment screw that is
separate from the base idle screw.
Here's how to locate it.
Note: Ever since Charter "fixed" my internet and cable after the lightning
strike, it hasn't worked right. Go figure. So, if you see this posted then
I was finally successful in getting a video uploaded.