my neighbor has a 56 with the 4000 carb which is flooding bad fouling his plugs.the car sat of and on for many years.i ordered a kit and was wondering is there anything besides the neddle and seat that causes them to flood.

Needle and seat are a main cause, usually just gummed up with old gas gum.
Running too rich can be caused by critters getting on top and clogging the air bleeds in the middle of the top cover, especially when the metal disc is not there.


1936 Ford 3W Coupe : 56 T-Bird 312, 47 Packard 3 speed, 40 juice brakes.
1968 Merc Cyclone FB GT 390, Getting a better front clip!
1977 Ford F-250 Supercab RWD Explorer Long box.
1976 Chev Camaro RS LT
Future rebuild : 1949 Ford F-1

To add to Robs good advice, another problem - those O rings for the secondary tubes have a tendency to dry out as well.  When they do, the tubes will leak extra fuel even when the secondary butterflies are not necessarily open. I don't know what brand of kit you ordered but I would suggest that you get something ethanol compliant - Daytona Carburetor is who I use. 

If you have time, visit some of my blog posts and videos...
https://www.hotrodreverend.com/post/rebuild-tips-tricks-for-the-holley-4000-carburetor

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Better call Sal.

Kind of want to back up a bit first, while the carburetor inlet needle & seat is of course critical they cannot be expected to function if the fuel pump output pressure itself exceeds limits, this is a common problem today and often overlooked.

Output pressure is easily measured using an ordinary Mechanic's vacuum gauge. No special contortions or setup is required either, simply connect the gauge to the fuel pump outlet and crank over the engine. Engine doesn't need to be running.

With the fuel pump pressure verified to be within limits, carefully adjust the float height to achieve the proper fuel height in the carburetor bowl. This is a key operating point for carburetor calibration, everything is predicated on this.

There is a large brass threaded plug on the back of the fuel bowl for access to the needle and  seat.  When the gasket on the plug leaks, fuel runs down into the secondary bores and into the intake manifold, causing very rich mixtures and lousy fuel mileage.  Also there is a brass transfer fitting between the throttle body and fuel bowl.  It has an O ring on each end, and if the O rings leak, again fuel runs down the secondaries.  There are gaskets and O rings in the carb kit for both of these areas.

John - "The Hoosier Hurricane"

the kit will be here first of the week.this thing was flooding so bad when you returned from a drive and took the breather of and shut it down the vapors would roll out of the carb.

All excellent advice and ideas.  One more item that could be responsible for flooding is a gas logged float.  Can sometimes hear/sense fuel in them when shaking and somewhere out there should be a weight spec in grams for that float. 

64F100 57FAIRLANE500

55blackties has the best idea.  These are not your usual Holley carbs and have quirks that most people don't realize.  In my experience and opinion, a pro that rebuilds these carbs for a living is the best way to go if you don't have experience with them.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Someone on another forum recently sent his 4000 "Teapot" carburetor to Holley to be rebuilt; he was pleased with the results. I think he paid $400+. I don't know what Sal charges, but he knows what he's doing.