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Tom Endy · 09-27-2019, 12:05 PM

If the comp jet (the one screwed into the fuel reservoir) is drilled out to the same size (or larger) than the cap jet, the GAV control will then have no affect because it will be the same as having the GAV wide open.

The early Zeniths have a brass GAV valve seat at the base, Ford did away with these in the later cars in favor of a cast seat because if you screw the GAV closed the brass valve could seize in the seat, then when you opened the GAV the seat would unscrew instead of opening the valve. Remove the GAV assembly and shine a light down into the tunnel to see which you have. If there is a brass seat there make sure it is screwed in tight in the casting

There could also be crud plugging either the cap jet or the comp jet. Blow all the jets out with compressed air or take them out and soak them in lacquer thinner.

Tom Endy

09-27-2019, 12:05 PM	#11
Tom Endy Senior Member Join Date: May 2010 Location: Southern California Posts: 3,131	Re: (GAV) Not working?? If the comp jet (the one screwed into the fuel reservoir) is drilled out to the same size (or larger) than the cap jet, the GAV control will then have no affect because it will be the same as having the GAV wide open. The early Zeniths have a brass GAV valve seat at the base, Ford did away with these in the later cars in favor of a cast seat because if you screw the GAV closed the brass valve could seize in the seat, then when you opened the GAV the seat would unscrew instead of opening the valve. Remove the GAV assembly and shine a light down into the tunnel to see which you have. If there is a brass seat there make sure it is screwed in tight in the casting There could also be crud plugging either the cap jet or the comp jet. Blow all the jets out with compressed air or take them out and soak them in lacquer thinner. Tom Endy