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Carter BB1 carb rebuild kit


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I am trying to locate my problem with my carb rebuild. I get good idle with choke open and then the engine stubbles when I acelerate. Seems like it is starving for gas. The kit had a Daytona float valve which I used.

The carb rebuild kit representative states “Our Daytona float valve for the Carter updraft BB1 is #25-48.  The orifice is nominally .096 and is fine for the BB1 with gravity feed. The design of the valve. Allows a 12 - 15 %  increase in fuel flow. 

The Carter instructions for a gravity fuel system recommends an orifice of 0.120”.


Anybody have experience in using the Daytona valve for a gravity feed fuel system in the Carter BB1 CARB? I choose not to use the Grose Valve

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Stumble upon acceleration is not a function of a defective fuel valve.


Stumble upon acceleration could be a function of the accelerator pump not functioning, or issues with distributor advance, or???


If the fuel valve is too small, then issues would arise at constant wide open throttle.


As far as the design of the Daytona valve, it is my understanding that the Daytona valve is a reincarnation of the Parker Brothers valve. When Paul Parker was still producing this valve, we used maybe 250 or so for BB-1 Carters with gravity feed.


Paul made many different unusual valves for us for use with gravity feed, to include Detroit Lubricator (Packard), Johnson (Cadillac), and even some for the mighty Duesenberg model J. We had no problems, other than a couple of customers thought the neopreme disc was a cushion for the float, and installed the valve upside down ;)


I have not used any of the valves made by Daytona, we now make our own valves for the unusual applications.


EDIT: should be a simple matter to temporarily insert one of the small inline electric fuel pumps for a test.



Edited by carbking (see edit history)
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car king ,It is a pleasure to read "your articles. I had a similar problem with my Carter BB1  in my 28 DB  6. ^nice idle and no power on acceleration, or complete shut down when the pedal is pushed.. I think I found the problem, I am not sure yet until I fire it up again in spring. Looking at the carburetor from the bowl end, on the right there is a pin the size of a 3/16 drill (?) that is spring loaded (on the throttle body portion). The spring is locked in place with a small brass plug. Remove the plug and out comes a tiny coil spring .Above the coil spring is a small steel ball. The spring could be rusted/broken or the ball could  be rusted. When functioning properly that pin . when pushed down should spring back up. I do know what it is called but I think that is some kind of pump.

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Trini - that is the step-up jet assembly. There is a pushrod coming from a hole in the center of a plug in the upper casting that sits on the ball. That pushrod is vacuum controlled. The bottom "plug" is NOT a plug, rather a jet. The jet is available in different orifice sizes, and controls the amount of fuel delivered by the power jet. When the vacuum goes to zero on acceleration, the upper spring pushes the pushrod down, unseating the ball and allowing fuel flow.


If the coil spring is fatigued, the power valve will be open constantly, requiring the operator to change the setting for the main metering jet; then the engine would be lean under WOT.


The ball, the tiny coil spring, and the much larger coil spring in the top casting are all contained in the better rebuilding kits. We suggest these should always be changed during a carburetor rebuild.


Carter BB-1 updraft service



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Carb King , thank you very much . Yes,  there is a fine hole in the plug. But the coil spring is black and week . Do you sell the better kits ? I would like to get one. To keep your contact private may be you would like to PM me instead. Thank you.

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