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Old 10-22-2011, 03:38 AM
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A couple things to try...

Originally Posted by 69chevyLWB
Okay i looked it all over again. and this is what i found: the primaries are closed fully but it still will not idle down past 1000. the fast idle cam is freee and not preventing movement so it is not that.
If the primary throttle blades are all the way closed and the idle is still too high, the idle screw can be moved back out once the problem is found, so that you have idle speed control. If it's not touching now, it's only because something else is causing the idle speed to be too high.

A vacuum leak can cause a too-high idle. Try removing the vacuum lines one at a time and plugging the port at the carb and see if you find one that will drop the idle speed down when it's removed and the port in the carb plugged. There are also vacuum ports on most intake manifolds- do the same to them.

Did this particular carb EVER work right? If it did, the gaskets that were used at rebuild may have been the wrong ones, or if you don't know what the carb was like before being rebuilt, it may have already had the wrong gaskets in it and if you replaced them exactly, you recreated the original problem.

Look to see that the secondary throttle blades are not hanging open. Some Q-jets have a link that locks the secondaries from opening when the choke is closed. If yours has this link be sure it will work to keep the secondaries closed- this will show you the secondary throttle shaft is fully closed. Be sure the sec. shaft isn't twisted, allowing one blade to be open while the other is closed.
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