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1923 Buick fuel leak question


Darryl
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My 23-4-35 Buick had a electric fuel pump which I removed. I rebuilt the Stewart vacuum tank and connected that to the carburetor. The problem I am having is after the engine is turned off. The fuel bowl slowly fills up beond the float level, takes about an hour, then leaks down the needle valve tube and out the end of the carburetor by the air intake. I have adjusted the float and cleaned the float valve and seat without any luck. I now turn the fuel valve off, on the bottom of the vacuum tank, to stop the leak.

Is this normal or do I have some worn parts?

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Darryl, unfortunately, this is a common issue with the vacuum tank system and the gravity fed carb. Most, if not all, turn off the fuel at the tank when we stop the engine for almost any duration of time to avoid the overfilling of the carb bowl and the draining of the vacuum fuel supply. I have not heard of any solution so look forward to seeing if anyone has more ideas.

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I have a 26 Buick which i put a shut-off valve at bottom of vacumn tank. Later on I found a fellow in CT who made me a seat with viton tip. Worked good. when I rebuilt the motor I turned the intake upside down and used a single barrel stromberg down daraft carb with electric fuel pump. I know its not orginal but sure works super. i have done the same to my 27 Buick woodie.

Just my thoughts.

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I have the same problem on both my 1920 and 25. I turn the vacuum tank off to stop the car, that way I don,t forget to close it and come back later with fuel everywhere which as silerghost said, a real fire hazard. I,ve tried adjusting the float, reseating the needle etc, etc, I think the needle and seat only have to be a tiny bit off centre and they leak. My carby was rebuilt, and still the problem. there is side play in the pin that holds the float and needle, maybe a shim to stop that side play would work, as long as it doesn,t prevent free movement.

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Yes, this is a common problem. Road vibration tends to beat up the needle valve and seat. The solution is to either have a viton tip needle valve made or in some cases you can use fine polishing compound to lap the needle valve to it's seat again for a good seal.

Most just use the shut off valve every time they stop and some (like me) forget to open it again when they start up again....

I usually get about 20 feet before I run out of gas....then my wife reminds me....

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I have no idea if the carb in my 24 Buick leaks or not because I always shut off the gas at the vacuum tank. It's just good practice with any antique car, especially one with a cork float carb that may finally saturate and sink sometime during the night or while in storage, etc. and make a huge problem.

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All,

I run my Kissels on the stock Stromberg carbs and Stewart Vacume tanks, which were 110%perfectly restored. Yet I also have this problem and tried everthing to fix it. The problem is that the Vacume in the Stewart tank, over several hours, will gradually release as these are not finely machined apparatus. That is just the way they are. The only method that worked is just using a fuel shutoff valve below the Stewart tank. It is a sure fix, and not really a bother. The valve only needs to be used overnight as the tank will hold the vacume for hours before it loosens up.

Thanks, -- RON --

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Ron,

The function of the Stewart tank is such that when the engine stops, the vacuum stops as well. The tank does not hold a vacuum after the engine is shut off. The problem with leakage is that gas remains in the Stewart holding tank under it's own head pressure. While the pressure is low, it is also constant and even the smallest leak in the float valve will eventually result in a spill.

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Stewart vac tanks, great while they work; a pain in the #@&~ when they play up.

Good practice with any vintage car is to turn off the fuel at the vac tank bowl filter.

One thing to check is to make sure the fuel system is clean and all screens are free of crud and dirt causing fouling of operating parts.

I run an injector additive in the fuel of my 27 Olds occassionally this helps to remove scum and build upon valves needles and sceens etc.

( We have lots of technology why not use it to keep our old cars efficient)

Also I have installed is a fuel solenoid valve in line just after the outlet of the vac tank and before the carbie, this eliminates the problem of overflowing fuel out of the carbie and flooding when I have forgotten to turn off the stop cock when the car is turned off.

The soleniod is wired to the back of the ignition switch "on" position via a fuse.

This allows the vac tank to retain it's head of fuel on the carburettor without the loss of fuel.

Usually the problem with the fuel system is the fuel float/ needle valve in the carbie as the vac tank does its job well.

regards

Andy

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I found a 12volt DC solenoid valve locally from refrigeration parts wholesaller.

Forget to mention my old car runs 12 volt system.

although a decent resistor should reduce voltage.

Lots of modern Air conds use 12 volt DC and less for coils etc

As a refrigeration man this was easy to track down a compatible valve and coil (used is an Alco 1/4" SAE refrigeration thread flare fitting.)

[does look a bit ugly but safe]

Solenoid valves and coils used for refrigeration must cope with oils, high pressures and be compliant to very high standards including explosive refrigerants such as propane. So low pressure petrol would less risk?

Check with your local manufacturer/supplier if the valve and soleniod is okay to run on petrol system prior to installation.

Most refrigeration components still come from the USA

Refrigeration components can make good alternatives as they have the same threads SAE type (prior to unified threads) and 45 degree angle flare as old fuel line fittings.

Regards

Andy

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