I have a 1984 Ford F150 with a Holley dual bowl carburetor, and the secondary bowl floods.

I replaced both of the floats, in case they have lost their buoyancy, and the primary bowl seems to be working OK now. The engine will idle BUT gasoline drips from the secondary bowl, and even into the secondary ventura at idle.

I adusted the external float level adjustment until the needle valve is totally closed, but it still floods.

It would seem that the needle valve must not be sealing, but with the weight of the float resting on the needle valve, I can't blow any air past it.

Any ideas?

Blowing air may not show you the problem. Did you try replacing the valve and seat ? 2 reasons the air might not work. 1) you can't really see it. 2) more then likely its at a much higher pressure then the fuel so it mat caus a seal to be created using the extra pressure.

Upon further thought, I may not have run the engine hard enough to use the fuel out of the secondary bowl after it had overfilled.

Another question:
How do you determine when the float is set properly?
I see the plugs in the side of the bowls and assume that when gasoline just runs out, that may be correct. Or should the valves be backed off from that point? How much?

Thanks for your response.

On the first nasty carb I rebuilt m I frgot to tighten the valve into the body. The valve seated fine, but the valve body leaked. I just had ro take off the top and tighten the screw.

Hollies are notorious to set up.

On the carb I had, fload ajdustment was simple. There was a glass bowl port. Fuel level had to be in the middle.

On the first nasty carb I rebuilt m I frgot to tighten the valve into the body. The valve seated fine, but the valve body leaked. I just had ro take off the top and tighten the screw.

Hollies are notorious to set up.

On the carb I had, fload ajdustment was simple. There was a glass bowl port. Fuel level had to be in the middle.

On this one, the valve bodies are threaded into the top of the bowl, sealed by a little "O" ring and the fuel level is adjusted by screwing the valve body either further down or up, locked by a screw head on top on the outside. All adjustment is made from the outside.

I just don't know how to determine when it is right.

Here you go:

Shut the engine off. Use a screwdriver to remove the sight plugs located in the float bowls on the passenger side of the carburetor. Fuel should be level with the bottom of the sight plug. If not, adjustments can be made to raise or lower the fuel level with the adjustment nut on top of the float bowl. Loosen the top lock screw with the screwdriver and use the 5/8-inch wrench to turn the nut, which is the adjustment. Turn the nut clockwise to lower the level of fuel or counter-clockwise to raise the fuel level.

Ref:
How to Adjust a Holley Carburetor | eHow.com (http://www.ehow.com/how_5332662_adjust-holley-carburetor.html)

Here you go:

Shut the engine off. Use a screwdriver to remove the sight plugs located in the float bowls on the passenger side of the carburetor. Fuel should be level with the bottom of the sight plug. If not, adjustments can be made to raise or lower the fuel level with the adjustment nut on top of the float bowl. Loosen the top lock screw with the screwdriver and use the 5/8-inch wrench to turn the nut, which is the adjustment. Turn the nut clockwise to lower the level of fuel or counter-clockwise to raise the fuel level.

ref:
How to Adjust a Holley Carburetor | eHow.com (http://www.ehow.com/how_5332662_adjust-holley-carburetor.html)

That's what I was looking for. Thanks!

Now if there's no other problem-------!!