An old time carb rebuilder I’ve used and one who rebuilds Holley 4000’s for one of the larger Thunderbird/ Ford car/Mustang parts suppliers told me 8 years ago the accelerator pump material did not work well with the ethanol blended gasoline. Has that been addressed in the recent years? 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

One thing not mentioned: The rebuild kits all have neoprene/vitron needle tips.  Alcohol fuel eventually makes the tip gummy/sticky.  I installed a NOS brass tip and never had a problem since.  Of course, THAT ‘teapot’ issue causes the opposite of the O.P.’s ‘flooding’ problem, but just thought I’d add it to the Holley 4000 discussion.

6 VOLTS/POS. GRD. NW INDIANA

They've gotten a bad rep over the years, but mostly undeserved. Ford had no problem putting 2 of them on the 57 E-code. There is a do-it-yourself modification that will allow you to use a 57-up distributor with the 55/56 carburetor. See Ted's article on eatonbalancing.com.

thanks for the advice.i rebuilt lots of 2100 and holleys over the years but these sure are different.these are good carbs when everything is in order.they were great on fuel as well.

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.

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

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

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.

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"

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.