Holley 4160, vacuum secondary ?'s

[PKRWUD]

There is a very tiny hole just below the lip of the primary and secondary venturi that are on the same side of the carb as the vacuum secondary diaphram. This is where the vacuum comes from. It is created by the air rushing into the engine. This is one reason why the vacuum secondary is so superior to the secondaries used in AFB and quadrajet style carbs. The carb will never be asked for more gasoline than the engine needs.

I'm sure you have vacuum to your diaphram, but your diaphram may be bad.

Remove the 3 screws that mount the housing to the side of the carb, and remove it. Watch for a small cork gasket right inbetween the two middle screw holes.

Push the diaphram arm up, and place your finger over the hole on the side, between the two screw holes. If the diaphram is good, the arm won't move when you release it, until you move your finger.

Take care,
-Chris