Project: Leaking Carburetor
When the TBird was delivered to California from Pennsylvania, it emerged from the car carrier belching smoke and stinking the neighborhood with gas. It was clearly a risk to run the car at all - given the possibility of a spark somewhere under the hood igniting the spewing gas.
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On inspecting the carburetor, we noticed that the left secondary tubes, pictured, was seated poorly.
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The mystery source of the leak became clear from this recording. A gap in the fuel stem that directs the incoming fuel to the top of the carburetor is causing some of the fuel to exit and spill into the inlets. Here is the mechanical schematic that shows it more clearly (see part 47, the fuel inlet fitting, and 48, the "o" rings for the fuel inlet fitting).
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Was this the source of the leak? The only way to know for sure was to start it up.
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But given the risk of again starting the car, it was important to quickly identify and record the source of the leak. So, with the help of my three children positioned at strategic locations around the engine and with their cell phones video cameras trained on the carburetor, we cranked it up. This is what we recorded.
Ordering Replacement Parts
This exploded view of the Holley 4000 helps to identify what parts likely need to be replaced. (The original Holley manual can be found HERE.) The "O rings" (part 48) on the fuel inlet fitting (part 47) will most certainly need to be replaced. Also, as the carburetor will be removed from the engine block, the gasket that separates the two will need to be replaced. And, while we are at it, the fuel filter screen (part 53) probably is well overdue to be replaced. Although it seems the secondary tubes (parts 9 and 10) are not a part of the problem, I'm going to play it safe and order the washers and o-rings for them as well (parts 61 and 62).
The parts were ordered from Mike's Carburetor Parts. Mike and his team were SUPER helpful - not just with supplying the parts, but also with providing advice and feedback on the above. The order:
After removing the carburetor from the motor, a 1/4" thick gasket was found to be sitting atop the engine block. It needed to be removed and a replacement part ordered. But what is it?
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Time to again consult Mike at Mike's Carburetor Parts. Mike came thru again - identifying the piece as a "phenolic spacer" - which he did not stock. But, he pointed me to someone who did: dashman.net. A few days later, the replacement piece arrived.
Removing the Flange Gasket
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Putting the Beast Back Together
Mike, of Mike's Carburetors, has a series of videos that served as a helpful reference for putting the carburetor back together:
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2020Aug25: Chuck Rosa, carburetorsandmore.com (email at carburetorsandmore@earthlink.net) is bringing the Holley back to life.
2020Aug31: Chuck Rosa, carburetorsandmore.com has restored the functionality and beauty of the carburetor - nice job Chuck!