Q-jet overhaul

Rochester Quadrajet parts description and overhaul discussion

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for Tim - Rochester tips





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 measure and adjust Quadrajet float level
I have had several requests for this, so here you go: 1. The airhorn has to be removed to do this, but the carburetor does not have to be removed from the engine. 2. Some data says to measure from the toe(end that is opposite from the hinge), some say 5/16 inward from the end, etc. I suggest following the specs for your particular carburetor. 3. With the float in the raised position and the inlet needle lightly seated, measure from the top of the float to the top edge of the carburetor with NO gasket in place. If you have to adjust the float, bend at the area that has the cutouts, 4, If you are experiencing flooding issues then it is an excellent time to install a new needle/seat and float and that should cure flooding problems that are not choke-related.





More Quadrajet tuning, some things! Part one in this saga on Sept 13, 2010
The car has a slight stumble and surge at a light throttle cruise at about 55 to 60 MPH. By swapping out the .050 metering rods to .048 units, the stumble and driveability concerns are now gone. Going richer would mean worse fuel mileage one may think? No! Now that the mixture is right, LESS throttle opening is needed now, which means higher vacuum, and this way the metering rods will block off the correct amount of fuel, and in the proper timing and percentages, so the car runs much smoother. As stated many times, patience and reading up on, and understanding how these intricate carburetors work will help out very much! Enjoy!




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