Too little - Too much ???

[mgreenfield]

As long as the fuel/air mix is OK, there's no way for an engine to get more air than it needs at full throttle, especially with a CV carburetor. Some engines are designed for and built with superchargers or turbochargers to "force feed" air into the engine.

Every intake mod I know about puts more air/fuel mix into the engine. Larger carbs, larger & smoother intake manifolds, porting/polishing intakes, larger and/or more valves in the head, more aggressive lift in the cam lobe shape.

[scooterollie]

jak;
I wouldn't automatically assume the sound you hear is the result of too much air. Pull the plug and do a read. See Stan's website for plug read info. My 150 gave the same sound at WOT and the mixture was fine. In fact, after opening the air box, I removed one of the two styrofoam blocks, covering additional in-flow holes, allowing more air to the filter and the noise you describe increased a little. This noise could be "muffled" with an extensive air intake system but why do so?