I call BS on this whole thread.
The air from the filter runs through the air horn, into the Venturi, past the throttle shutter, and into the engine. A clogged or faulty/dirty air filter will result in dirt getting into the engine, or into the throttle bore of the carb.
Any dirt INSIDE the carb is coming from the fuel line/tank/filter...
With the exception being the fuel pump chamber vent..but it's never an issue, and is isolated from the wet parts of the inner carburetor.
Your dealer is a liar who doesnt know how to work on saws, he just likes to stick his head up his a$$ and spount non-sense on gullable customers...
If a "tech" tried to pass that bullstuff on me Id set his a$$ straight....