Vacuum Secondaries

As noted above, the external vacuum lines have nothing to do with it; the vacuum passage for this is internal. The above small ring gasket could be lost or cracked, plus the vacuum diaphragm inside the vacuum pod could be punctured/torn, or installed wrong....as mentioned.

There is a rod from the primary throttle shaft that links from a cam on one end of that shaft and links to a cam on the secondary shaft; this is the lock-out that makes sure the secondaries are closed at idle and is on the left side IIRC. Make sure that linkage is all in place properly and not binding; you can rotate the primary by hand and see where it releases the secondary so that it can move IF enough vacuum signal in the primary throats is present. While checking this, open the primaries fully by hand and then turn the secondary shaft lightly by hand; you ought to feel a bit of resistance (that is the vacuum pod's airflow restriction fighting you) but the secondary shaft should turn smoothly almost 90 degrees; when you let got, it should close by itself.

These will not typically open at low RPM's but only at high RPM's. So dead stop WOT without running the revs way up will not open them, especially on a larger one.