Originally Posted By shorthorse
That's a good one. I just checked Holly's instructions for the HP 80509-1 on-line. There is no mention of a center adjustment screw like the Demon has.

The air bleed screw under the air cleaner stud is a feature that wasn't introduced until the later aluminum "Ultra HP" 4150 carbs. Those are the 8080# series, such as the 80805 850 version.

Last edited by BradH; 06/05/15 01:06 PM.