My son just bought a 70 skylark with a 350 and 4 bbl Q-jet. Carb # is 7040244 and the 350 is a high compression model. The carb doesn't kick down after starting and it is idling extremely high. I have not owned a car with a Q-jet so I looking for advice on how to fix these items without just clunking around. I have very limited carb knowledge so pictures would be very beneficial. I did do a search and did not come up with anything helpful. I will be buying a book on the Q-jet as soon as possible. Thanks for any help you can provide. Bill
Well, there are a number of possibilities. First thing to check is the choke linkage. It may simply be gummed up. Get a can of gumout and spray all the exterior linkage. The choke plate and linkage should move freely. The choke is operated by the choke thermostat. It is a coiled bi-metallic strip that expands and contracts with the temperature. It sits in a pocket on the intake manifold, and it has a single link to the choke blade. Sometimes with age, the thermostat loses it's ability to operate. Most times, they last a good long time. With the engine cold, air cleaner removed, open the throttle all the way and then close it. If the choke thermostat is working, it should move the choke blade fully closed. If you push the choke blade open with your finger and let it go, the choke blade should spring closed again. When you start the engine, the choke blade should open about 1/4". There is a vacuum operated choke pull off on the front passenger side of the carb that opens the choke that much so the engine will run smoothly without loading up. Make sure that this choke pull off is retracting when the engine is running. There is a passage under the intake manifold that crosses from one side to the other. Engine exhaust heats the choke thermostat pocket and as the choke thermostat gets this heat, it opens the choke blade. A popular performance mod is to block off the exhaust crossover so that the intake and carb remain cooler. If this is done, the choke will come on, but will not come off because the choke thermostat is not receiving the heat it needs to operate. If the intake manifold doesn't become hot to the touch within a few minutes, it might mean the crossover has been blocked off. The previous owner may know if this has been done. There is a small cam that rotates with the choke. The cam has different steps that cause higher idle speeds. If the choke isn't opening as the engine warms up, the idle will remain high because the cam isn't rotating to it's lowest idle position. Hope that helps.
It does, kinda. I monkeyed with it last night and found a small screw on the drivers side that makes contact with the throttle linkage(?). Anyway when I unscrewed it, it did raise and elevate the idle speed. There was also a vacuum diaphragm looking thing attached to the manifold that making contact. I loosened the nut on it and screwed it out a couple of turns so the linkage could travel further. Whatever I did seems to havev worked because the idle is fine and the car no longer diesels when you shut it off. I need to get some books on this car and it's components. THanks for the help.
