VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Carb leaking gas at throttle body

Hello all, I have a Carter Carburetor W1 in my 1946 Chevrolet Fleetmaster with the original 216 straight six. In the early spring, when I went to start it, I smelled gas to find the carburetor soaked. I got a rebuild kit, rebuilt the whole carburetor (although it didn't seem too bad) and put it back on the car. I drove it occasionally throughout the summer without any problem. Today, I gave it one more drive before winter. I pulled it into the garage to park it and when I returned to the car about an hour later I smelled gasoline. Sure enough, the throttle body of the carb was soaked in gas.

First question is what causes the carb to leak from the bottom? I could see a sticking float or needle to leak from the top out of the bowl, but the top of the carb is completely dry.

I would think (and hope) that another rebuild is not the problem here. Anything simple that I am not seeing or is the carb finally shot after 75 years?

Thank you,
Matt

It is overfiling and has too much fuel in the bowl. Could be caused by incorrect float level, leaking needle valve, fuel expansion due to heat or stuck heat riser or?

Gene, thank you. In the carbs I am accustomed to (1950s and newer), there are vent stacks in the air horn that bleed if the float level is wrong. For the W1 carb that I have, I do not see those vent stacks - so does this mean if the float was wrong, it would manifest at the base? Just trying to think of the path the fuel would go.

As for heat, I am running at about 180 degrees on the thermometer. Over the summer, it sure did get hotter.

From the troubleshooting section of my website:

https://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak

Matt - the vent is the 1/8 inch brass tube sticking up in the air intake at approximately a 45 degree angle.

Jon.

Jon, this is phenomenal. I learned quite a bit. Thank you VERY much!

For what it is worth, I only run 87 octane non ethanol in the tank. I will try the tips offered on your website.

Again, thank you very much. Always learning something new.

The heat riser is a flap in the exhaust maifold below the carburetor that is thermostaticle controlled to heat the area under the carburetor when cold. Often rusts up and gets stuck heating all the time. The counter weight is sticking out of the front of the exhaust manifold.