My saw has the black cover for the grill in the air box, and the manual says to remove it and store in the lower portion of the air box cover for cold weather conditions. The black shutter in the engine cover was not installed on my saw, although there is a provision for it, and the manual says that it should be closed for warm weather use, and open for cold conditions.
My thoughts were if this were open in warm weather it could affect the cooling of the motor, possibly causing it to seize. Have you guys seen other saws without this shutter and running in hot weather successfully?