Joe - the idle circuit on the W-1 has an inverted "U" shaped passage. This passage runs up from the idle tube to a horizontal cross-over, and then down to the idle port.
Since these carburetors are cast-iron, occasionally I see one with this passage completely blocked which prevents the idle circuit from functioning, and the carb will only idle at higher RPM on the main circuit.
This circuit is accessable by removing the three copper drive plugs (1 for the vertical from the idle tube, 1 from the horizontal cross-over, and 1 from the vertical down to the idle port).
You should be able to blow compressed air through this circuit from the hole from where you removed the idle tube, and have the air exit at the idle discharge port. If not, the passage is plugged.
Jon.
