Q-jet Carburator Tuning

QJet tuning question - Third Generation F-Body Message Boards

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost , you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today ! First off, I replaced the choke thermostat but when I took the old one off I didn't realize it was under tension so I'm not sure what position the flap should be in when I put the new one on. I think I may have busted the new choke thermostat because I installed it one way and when I cranked it up the first time after a few minutes when I reved it up a noise came from the carb and it ejected some gas out the top (almost like a backfire out the carb). So not sure if that is related to the choke or something else but it only did it that one time and has not done it again since. First off, I replaced the choke thermostat but when I took the old one off I didn't realize it was under tension so I'm not sure what position the flap should be in when I put the new one on. I think I may have busted the new choke thermostat because I installed it one way and when I cranked it up the first time after a few minutes when I reved it up a noise came from the carb and it ejected some gas out the top (almost like a backfire out the carb). So not sure if that is related to the choke or something else but it only did it that one time and has not done it again since.. So, when you install your thermostat, you want to make sure the "tang" on the thermostat goes over the "finger" on the carb. Fairly self explanatory when you're looking at it. Then you basically turn it so the electrical connection is flat (parallel with the ground). Slight adjustment may be required, but basically you want it to *just barely* close the choke flap when the car is stone cold. Your choke has 3 settings, what I just described above is setting the thermostat - aka - setting the duration, and how cold it has to be for it to kick on. The second part is the screw on the vacuum break. That sets how far open it'll pull the flap, so the engine doesn't suffocate when it's first started. You can push in the vacuum break mechanism, then adjust the screw so it cracks it open ~3/16". That keeps it from stalling when cold started.

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