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Old 01-11-2019, 09:13 PM   #1
doa44green
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Default Zenith mystery again.

I have 9 Zenith carbs. When I place just the bottom half in my vise and fill the bowl with gas to the 5/8" level they all will wick gas up the inside of the bowl, collect on the gasket surface and overflow to the outside of the bowl. The GAV and jets are installed. This has nothing to do with the float valve or any gas line connections. I also have the bottom half of a early Holley carb. which does not leak using the same testing technique.
Can anyone please explain if this is common to all Zeniths? Is there a product to apply inside the bowl to seal it?
I am baffled!
Thank you very much for your input!!!
Don
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Old 01-11-2019, 09:37 PM   #2
Gary WA
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Default Re: Zenith mystery again.

Do Not Seal inside Carb!All jets need one gasket, except Idle Jet, and properly tightened. If the Carbs have not been used and dry The Carbs will absorb gas into the metal of the carb. I have never had one do what yours are doing. I do a lot of rebuilding for members no problem.
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Old 01-11-2019, 10:10 PM   #3
Rich in Tucson
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Default Re: Zenith mystery again.

I think what you are experiencing is not a feature of the Zenith carb, but of modern gasoline. Your modern gasoline may have more or less alcohol in it than mine and behave differently in Zenith bowls; I adjust the float level in every carb to what works on the engine it is meant for, after testing jets for flow rates which can be controlled, not to some arbitrary measurement of gas level in the bowl. After time has passed and after whatever has been done to the metal and passages of carb bodies (which cannot be controlled), each has to be individually restored, if it can be. I would be interested in knowing the results of the same test in 8 more Holley carbs...
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Old 01-12-2019, 01:24 AM   #4
redmodelt
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Default Re: Zenith mystery again.

https://www.fordbarn.com/forum/showthread.php?t=257165


Best to keep all this in one place.
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Old 01-12-2019, 01:36 AM   #5
redmodelt
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Default Re: Zenith mystery again.

Why not assemble the carb(s) with proper gaskets and try your test then.
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Old 01-12-2019, 04:44 AM   #6
johnbuckley
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Default Re: Zenith mystery again.

Doa44Green, sounds like you are looking at capillary action on the fresh surface of the gas bowl. Try just putting in about half and inch of gas very gently, - you'll see the sides of the bowl getting damper above the surface of the gas as it as it wicks upwards because of the rough surface of the casting ( like paper sucking up water). Once the casting absorbs sufficient fuel then the wicking is not great. level the half inch for a few minutes then top up, the actual level should now pretty well be settled at 5/8 in.
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