Why is my Holley Carburetor Flooding?

• Leaky needle and seat are the most common. See this page on how to test it
• Float leaking. Nitrophyl floats are solid but can absorb fuel. Weighing in grams is the only way to test this type.
• Float sticking. Move the float up and down by hand to see if you can feel any binding.
• Engines that have been sitting for several months can be a problem. Gas turns into varnish then coats the gas tank and the carburetor. Fresh gas is not the solution.
• Bad power valve. If the power valve is leaking then extra gas is being transferred to the main circuit. This will usually cause a richness and not necessarily flooding.
• Dirty or plugged passages. A rebuild may be needed. Blow out every passage, or spray carburetor cleaner through each passage.