zenith 1 overflows.

[f balsiger]

my zenith carb overflows out the hole on the opposite side from the intake. I have installed a new needle valve and have lowered the float over I/8 inch and made sure the valve sealed manually.
I there an internal way for gas to get that high other than the needle valve or an internal fuel path that would vent through the hole next to the assembly bolt hole?

[Purdy Swoft]

If the jets are too short and below the level of the gas in the bowl of the carburetor it will continue to drip . I would also check the gasket under the needle valve assembly .

[Brentwood Bob]

Has the float been checked? A worn float can wear causing the fuel valve to stick. The float can loose bouyancy. Even new valves stick, the Viton valve can stick, the seat in an OEM valve can wear.

[Keith True]

Check the vent opening in the carb top half,where it vents the bowl to the atmosphere.If a bug gets in there,just the trapped air will not let the float rise up and shut the valve off.they will start to leak a few seconds after you shut the engine off.

[Purdy Swoft]

A small hole in the float will cause the float to leak and get heavy . When the float leaks and gets heavy it sinks and a much worse leak begins .

[30 Closed Cab PU]

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Interesting the leak is coming out the bowl vent hole. Typically a gas leak comes out the bottom seep hole in the bottom of the air intake, or the bottom of their intake if the seep hole is plugged or painted over.


Another cause is shim washers on the float valve, sometimes they seep. Usually using the red type shim washers remedies this issue.

[Joe K]

The test for a float leak is to immerse the float in water immediately taken from boiling. The heat expands the air inside the float and you see bubbles coming from the leak.



Joe K

[30 Closed Cab PU]

f balsiger - is it the hole on the bottom of the air intake, or is the hole towards the top of the float bowl?


When is the gas leaking - all the time, only after sitting for a couple of minutes, only after a couple of hour/overnight?


If you turn off the gas shutoff - does it stop leaking after a while?


Is it a slow/slow drip, or a stream?


Sometimes the float valve does not seat properly, and tapping with a wrench/small hammer on the float bowl stops the leak.

[f balsiger]

the leak is a study stream leading me to believe it has to be float valve. the flow is from the hole near the bowl air vent. I have tried 2 additional float and valve combinations same problem STYMIED!

[30 Closed Cab PU]

I do not now what is happening. Am not an expert but I would think if the gas in the bowl level is enough to leak out the vent, should be coming out the air intake/intake seep hole also?

[Purdy Swoft]

I would shake the float . Usually I can feel the gas sloshing around in the float if the float has a leak . This is fairly common . Some of the floats could be pretty old .

[johnbuckley]

I've problems with new float valves of whatever type and have to check them all!:
Here's the list of possible causes of Zenith leaks
Problem: Remedy
1 Leak at fuel inlet union: Tighten/reseal/replace
2 Loose/leaking gasket at strainer: Tighten/reseal/replace
3 Loose/leaking gasket at drain plug: Tighten/reseal/replace
4 Cracked casting/leaking passage plugs: Repair or replace
5 Leaking or loose GAV housing threads: Tighten/ reseal/ replace
6 Leaking/loose gasket at main jet: Tighten/reseal/ replace
7 Leaking /loose gasket at cap jet: Tighten/replace
8 Leaking float valve: (or crud stopping it sealing) Replace (or clean up if possible )
9 Leaking/loose float valve gasket: Tighten/reseal/replace
10 Friction on float hinge: Loosen
11 Hole in float: Repair or replace
12 Incorrectly set fuel level: Re-set
13 Too many gaskets on main jet Check
14 Cap jet or main jet too short: Replace