10/08/2026
I'm seeing posts about Holley carbs lately that are just plain wrong.
First thing's first. VERY FEW Holleys are double pumpers. What is a double pumper? I saw a video where a guy said if it's a mechanical secondary, it's a double pumper. WRONG!!!! Yet another said if it's a center hung float bowl carb with two fuel inlets, it's a double pumper. WRONG AGAIN! Every carburetor has an accelerator pump on it. It gives a shot of gas to cover the needs of the engine in transition from idle to wide open throttle. SOME Holleys (very few) have an accelerator pump on the secondary side. That means they have ONE, ...TWO accelerator pumps. DOUBLE. PUMPER.
If you have a carburetor with the split fuel line that feeds fuel to the primary and secondary float bowls, that would be a dual feed carburetor.
If you have a carburetor that will open the primary and secondary butterflies with the engine off, that is a mechanical secondary carburetor.
Most of the Holleys you see are 1850 series, 600 CFM. Single feed, single pump, side hung float, vacuum secondary.
I've also seen some absolutely HORRENDOUS advice being given about tuning. Straight up wrong information.
Long story short, make sure whomever you have tune your carburetor at least knows what they're talking about. Knows the proper terminology and knows what the parts of the carburetor do.
..and for God's sake don't listen to these 20-somethings on Youtube tell you how to adjust your carburetor. From what I've seen today, you have a 20 % chance of getting correct information.
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