I picked up a Tohatsu 9.8HP 4-Stroke this week and started break-in yesterday. I am getting a whine/whistle (sound like air movement) at low RPM (just above idle). It's not crazy loud, but it's noticable. The motor seems to run great. Has anyone else noticed this sound? It only occurs at a narrow RPM range (about 1000-1200 RPM).