Holley Needle and Seat Repairs Pg. 3
The top square "window" is where fuel enters the needle & seat, and the lower window is where the fuel exits the needle & seat into the float bowl. It's a little tough to see in the picture, but there is a small rubber point on the top of the needle which seals against the small hole above it. This is where the problem is. Look for any obvious debris here and remove as necessary.
Before reinstalling the needle & seat, a good blast of carb cleaner is highly recommended. Lastly, check that the needle operates freely & smoothly before reinstalling the unit. If it sticks, replace the needle & seat with a new one.
A few drops of light oil on the needle & seat and the o-ring helps ensure a smooth reassembly and helps prevent damage to the o-ring.
