Cruising down the highway, you come up on a slow-moving car. As you merge into the passing lane, you press the accelerator but your car doesn’t seem to pass as quickly as you think it should. Pondering the fact that you just purchased a new high-horsepower crate engine, passing a slow-moving car should be the least of your worries. You know the manufacturer of your engine is reputable, and the motor isn’t the reason for the loss of power. As you think back to the installation, you realize that you used an old Holley vacuum-secondary carburetor and it could be that those back two barrels aren’t opening up under acceleration. In this article we show you how to cure this problem without removing the carburetor.

The only tools you will need are compressed air and a high-flow air nozzle. Before starting any part of this procedure, make sure the engine is off and remains off until the entire test is over. You can do this test with the carb on or off the car, but be careful not to let anything fall into the engine. If any carburetor work is to be performed, we recommend removing it and covering the intake manifold opening. Begin by removing the entire air cleaner.