See 1976 Chevrolet pickup with Rochester quadrajet upgrade on SBC 350 V8.
We removed the hood, mounted a camera looking down on the air horn, and
took it for a spin, running wide open on an uphill grade. See how the
secondary air valve responds to rpm drop at each upshift of the THM. Also
included is a smoking burnout.
how to minimize engine bog with a Quadrajet carb
this is to minimize engine bog when the pedal is to the metal. do not over
tighten, very small spring...you want to try 1/4 turns or 1/2...q-jets are
good if tuned properly. also when you are tightening screw it will have
tension on it so keep the screwdriver firm. 1986 gmc sierra single
straightpipe to cherrybomb. you will need a small flathead screwdriver and
a 3/32 allen key. be sure not to tighten to much or else your vacuum
secondary flaps wont open.
How to debog your Quadrajet part 3
In the first two videos we looked at operational theory of the Quadrajet.
In this episode we'll explore a couple mistakes the home mechanic often
makes in an effort to improve the performance of this unit.
Rochester Quadrajet, the results!
Two mishaps, the first shown here, the choke coil I got was wound
backwards, it made the choke butterfly wind up TIGHTER as the engine warmed
up. I swapped on the one from the old carburetor fast enough, the second
mishap made me feel like a crud and what did I mess up later that evening.
The car would not start leaving the Etobicoke -Queensway show. It was not
getting gas. We got it running by priming the carburetor, and boy, was I
ticked at myself. In the end it was not my fault it looks like. The new
accelerator pump umbrella and rod was a very poor and frail design, the
umbrella came detached and stayed at the bottom of the of the pump well,
and was a distressed mess. The maker will get a note from me. The upshot?
The old assembly went in, all is perfectly fine, the slight tip-in
hesitation is gone now too. Stupid lack of pride it seems these days
making parts for even simple things like an old carburetor.
Identifying Quadrajet vacuum ports
I always see a lot of questions about what various vacuum ports do on a
Here's a general guide that will point you in the right direction.
Remember that there were many different Qjets over the years and vacuum
port locations and number will vary. This video is representative of
How to adjust carburetor mixture screws
Here's how to find and adjust the mixture screws on your carburetor.
Note that metering-block style carbs such as Holley and Demon more often
have one or 2 mixture screws in each metering block depending on the number
of venturi. Also those may not be located at the bottom of the carb as in