If the distributor has a vacuum advance, then the distributor will require vacuum.
The drip tube should be connected to a full vacuum port with a small orifice; as if it were connected to a say, 1/4 inch hole, it would create a huge vacuum leak.
The purpose of the drip tube was to collect fuel in suspension above the throttle plate (upper portion of carb, intake manifold) which would (gravity) drop when the engine was turned off, and the fuel was no longer held by engine vacuum. The collected fuel in the drip tube would then be pulled into the engine when the engine was cranked for starting (kind of a "starting circuit" in the carburetor (common on some older imports).
The drip tube was never designed to collect fuel leaking when the engine was running.
If the compression is good, then cranking the engine will put fuel in suspension above the throttle plate. Discontinuance of cranking would allow that fuel to drop.
I'm guessing the leak is a result of defective ignition, not a defective carburetor; but tests are in order. Guessing costs money; and often only results in frustration.
Jon
