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2025 C3 ('68-'73) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2019 C3 of Year Finalist (stock)
Adjusting throttle linkage
Got some great advice here from some of the guys on adjusting my Quadrajet... In doing so I discovered my secondaries are barely opening at WOT... I’m hoping I can get them to open all the way by adjusting the throttle cable. If the cable is already at its limit or that’s not the problem at all is there anything else I can look at? Can’t wait to hear and feel the difference when the quads are working correctly...
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I removed my pedal and put it in a vise to bend it. I didnt want to rip it right out of the floor trying to bend it or have to replace the plastic hinge
Also check the clevis fitting between the pedal rod and the arm.
Mine was loose and I was losing the last few mm's of cable pull with pedal mashed to the floor.
Tightened that up and she was getting to full throttle again!
Free HP!!
Last edited by Bergerboy; Feb 18, 2020 at 12:50 PM.
The secondaries on a Q-jet start to open near the end of pedal travel. So it is very easy to have one that has only partial opening....or doesn't open at all with the accel pedal.
You need someone in the car and depressing the pedal to set it properly. WOT should cause the carb linkage to go against the stop and the throttle plates should be exactly vertical, when properly set. Items between the firewall and the accel pedal can be a problem (ie, carpeting, sound deadener, insulation, floor mat, etc.).
Actually, the upper air valve is "airflow" regulated, rather than vacuum operated. But, your point is exactly right. The OP needs to hold the upper air valve open and look down into the secondary venturi to visually check throttle to carb throttle plate response.[engine OFF, of course]
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Adjusting throttle linkage
