Quote:
Originally Posted by P.S.
...Zenith that runs way too rich,
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Running rich is usually caused by the GAV not seating properly or the compensation jet too large. since you already have the carb and I assume the builder of the carb does not beleive you and won't take it back. Why not try to fix it yourself, what do you have to lose?
-The Gas Adjusting Valve provides a manual adjustment for additional gasoline to the Cap Jet, bypassing the metering effect of the Compensator Jet. The carburetor was designed slightly lean to allow for high altitude driving and, with the GAV, is able to provide additional fuel as needed. This extra fuel is normally needed when the vehicle is cold and at low engine speeds.
-The replaceable Brass Seat was used through 1929. -An integral Seat, Machined in the Lower Casting, was used after that.
-The Seat opening is honed to match the shape of the GAV Needle.
-Notice that the Brass GAV Seat looks much like the Compensating Jet.-However, they are different! They are NOT interchangeable. The Brass Seat is also longer than a Compensator Jet.-It is recommended to use a gasket under the brass seat.
-The Gas Adjusting Valve housing threads are 1/8" 27NPT (Pipe). Use Caution not to cut threads deeper, as it is a pipe thread.
-The GAV housing can become frozen in the pipe threads of the lower casting. The soft brass nut of the GAV is easily damaged beyond use. So, to remove such a GAV housing, cut the housing off just above the nut using a hacksaw. Then, remove the lower frozen part using a spiral screw extractor (Easy Out).
To obtain a good seat when Gas adjusting valve is closed, the seat sometimes needs to be polished to remove pits, dirt scratches, etc. This tool and guide provides a mating, aligned surface that can be spun against the seat with polishing compound on it. The tool is made by soldering two needles together, back to back. The end that will go into the guide and provide the polishing surface needs to have its threads removed to enable it to be spun continuously with a drill. Using an old GAV housing, the spring has been removed to let the tool spin more freely. Some people also cut down both ends of the housing.