Packard Forum Index » Post-War (1946-54)

I’m having a couple problems with my carburetor on my 1948 Packard Super Eight it has a Carter WD-0 model 643S.

The first issue is it won’t stay idling. I can start the car pretty easily, but then it idles for about five seconds, and then shuts off.
Timing is currently set to 6 degrees before TDC

The second issue that I have is gasoline leaking from the float bowl. I have tried turning the fuel pressure down to below three psi. I have also tried putting the float level way lower than where it should be.
Whenever I turn the fuel pump on, it will build pressure up to just below three psi (or wherever I have it set) then it will slowly leak past the needle and seat, causing the floatbowl level to rise until it spills out the top, where the accelerator pump is.
I have just had this rebuilt so it has all new gaskets, needle&seat, completely cleaned, etc.
Could someone with more experience help me out here?

You are describing the reasons why these cars need a vacuum tank, not an electric fuel pump. The vacuum pump feeds by gravity at negligible pressure.

Ok I will try hooking it back up to the original combination pump and see what happens. I have rebuilt it already but I was going to use the electric pump up until the engine had broken in as it was already there.

My electric fuel pump works great on my 49 Standard 288 as the only pump being used.

Try disconnecting the fuel line from the pump and pour gas down the line into the carb and see if it still leaks between the needle and the seat. Just because you had the carburetor rebuilt doesn't mean it was done correctly.

The 1948 model never had a vacuum tank fuel system. (Did it?) Fuel pressure with a stock pump was around 3 to 4 PSI, so if you have flooding issues with your fuel pressure accurately measured at 3-4 PSI, you have a carburetor issue, perhaps the float/needle/seat/gasket, dirt, or some other issue, such as a sticking float or internal leak. I'd look for dirt first of all.

There is no vacuum tank in the fuel system. I think those were gone by the late 20s or early 30s.

Sounds like a bad needle and seat, or more likely a float with a hole in it. Float fills with gas and will not rise far enough to cut the flow of gas. Take the Carb off flip it over 180 deg and blow in the inlet if you cant blow through its a bad float if you can blow through its a needle and seat issue.

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Like I said there is a brand new needle and seat- maybe I got a bad one? I will try blowing into the inlet again to double check but I’m pretty sure it held in the past. I also have a spare float from my parts carb I can throw on if needed.

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I am currently using a regulator with a fuel pressure gauge both brand new so I am confident in the accuracy of my measurements. I will also double check and re clean out any dirt when I take it apart again in a few hours.
I will come back with an update once I do these things.

Dirt can be very hard to be completely rid of in older fuel systems. The glass bowl type filters can be helpful in detecting and catching dirt.