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To repair Holley carburetors, Granger recommends using either a Holley rebuild kit and gaskets or a quality aftermarket kit. Inferior gaskets can cause driveability problems or fuel and vacuum leaks. It's also important to use the proper tools. Flare wrenches, correct-size screwdrivers, and a clean work space all contribute to a quality rebuild.
Is your carburetor giving you idle problems?
- If so, start with the basics. For most Holley carburetors, the air/fuel mixture screws should first be set to 1-1/2 turns outward before their final adjustment. Always adjust all idle mixture screws evenly.
- To allow your distributor's vacuum-advance unit to operate properly, the hose should connect to a ported vacuum source and not direct vacuum. A good test for this is to remove the plug with the engine idling and check for vacuum. There should be none at idle.
- When wiring the electric choke on a Holley carburetor, run a 12-volt source from a switched terminal. Never connect the choke to the positive side of the coil.
- An air cleaner not only delivers clean, undisturbed air but also minimizes the chance of a fire spreading in your engine compartment. Also make sure that the air-cleaner lid does not block or interfere with the carburetor vents. If this happens, stalling can occur.
- After installing the carburetor, check wide-open throttle (WOT) operation. For proper throttle return, install a return spring that is just strong enough to pull the throttle back. Too strong a return spring can cause unnecessary wear to the throttle shaft and bushings.
- To remove a stubborn fuel bowl, tap it with a plastic mallet. Using a screwdriver to wedge the bowl away from the carburetor body could create a permanent leak.
- Be careful during reassembly because over-tightening the carburetor can strip threads.
- When checking accelerator-pump operation, remember there should be no clearance between the actuating-lever screw and the diaphragm lever at idle. When adjusted properly, the diaphragm lever should be able to move enough beyond WOT to accommodate a 0.015-0.020-inch feeler gauge as shown in the photo.
- All gasket surfaces should be cleaned carefully with a wire brush to remove old material.
- Use a wide-blade screwdriver or a jet-removal tool when replacing a jet. The wrong-sized screwdriver could damage the jet's orifice and affect the flow.
- Work in a clean environment to prevent debris from entering the open carburetor, and remember to blow out all passages with air before reassembly.
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