I hate when I am wrong. I wanted to know why that article would say what it did so I looked here and there for information on the CVK pilot circuit and then went back to that article.
They are absolutely correct.
First, Id' like to give some info on the venturi effect for my own benefit as well as yours. Check out this graphic. I know you all recognize it (except for the yoots!
):
High pressure from the ram exits the tip at a lower pressure but with a higher velocity (the
venturi effect which is an aspect of Bernoulli's principle) which sucks whatever fluid is in the can up and sprays it out. What if we introduced a metered air control into the can and opened it up (counter-clockwise)? Less fluid would be sprayed! Lean! Closing it (clockwise), would richen the spray!! Less air, more spray! Like I said, I hate to be wrong...
Anyhoo, I broke the animated graphic out into its two pics as I wanted to look at the idle side. Here's that graphic:
First, I was mistaken about where the venturi effect is taking place. It actually occurs in the throat of the carb itself and the outlet for the pilot jet's gas and air screw's air (right below the 'P' in Low Pressure).
Check out the green (air) and purple (gas) bubbles (sheesh, how corny!
). Air flows (red arrow) into the carb passing over that outlet. If you screw the air screw in (clockwise),
it will richen the circuit because more gas will be sucked by the pressure differential between the tube and venturi instead of air. If you screw the air screw out (counter-clockwise),
it will lean the circuit because more air will be sucked by the pressure differential between the tube and venturi instead of gas.
So how does this affect popping? My theory is that if you richen the circuit (screw the air screw in, clockwise), you're introducing more fuel which produces popping. If you lean the circuit (screw the air screw out, counter-clockwise), you have an opposite effect.
Have some coffee and discuss!
This is correct if the air mixture screws are on the air filter side which ours ARE NOT. Dang it!
