Yes Max, you are missing something. The flow rate for any given
combination of needle/jet position is dependent on the difference
between atmospheric pressure pressing down on the surface of the fuel in
the float bowl and the pressure in the venturi. The pressure in the
venturi is lower than the pressure in the bowl. the atmospheric
pressure in the bowl pushes the fuel thru the jet into the lower
pressure environment in the venturi. Now, we know that as you go deeper
in a body of water, the pressure increases. The same thing happens in
the microcosm of the float bowl, albeit the pressure change is very
small. That's why the float height affects the mixture. When you tweak
the needle adjusting nut, you compensate for that, among other things.
As I stated in another post, I've experimented with different float
heights. I found it to be a waste of time if the jets are going to be
readjusted, because the jet adjustment cancels out any reasonable change
in the fuel level. Once it's determined that the float valve is
functioning correctly, the thing to do is experiment with different
needle and/or jet combinations, IMHO.
Cheers,
CR
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