GAV Adjustment

[spdway1]

Hello group,
Happy Holidays! I have owned around 15 Model A's in my lifetime. I just took delivery of another one last week. I find it interesting that it runs near perfect with the GAV a bit over TWO turns out . I have never experienced this in any previous Model A's. Do you think there is an issue or concern?
Thank you for your input.

 

[nkaminar]

Check the size of the hole in the main jet. Find a drill or wire that just fits and then measure it with a micrometer. Then check with the specification. Also check that the tip of the main jet is right at the throat of the venturi. See https://modela.org/main_jet.html

 

[johnbuckley]

I would never advise poking wire or a drill through jets!! Clear them with an airline or do flow testing. Some things to consider also .... A, main or comp jet partial blockage or too weak. B, manifold leak. C, general gunge in carb. D, brand of fuel. E, I have found Tillotsons usually require GAV 3/4 to 1 1/2 turn as opposed to the Zeniths 0-3/4. I wouldn't worry too much - it may be self-remedying unless it's a manifold leak.

 

[Bob Bidonde]

I suspect the idle jet circuit has an issue also.

 

[Will N]

Maybe a vacuum leak around the intake or carb mating surfaces?

 

[gdmn852]

Hello, check flout level will effect GAV position. I clean out the cast iron passages in the carburetor body but never the jets ,!can be sized, by silver solder and redrill and ream , but for Model A s easier to get other jets .