Flywheel movement

[ptbrakefield]

It has the rattlesnake sound but in low to mid rpm. Maybe at top end it's happening too fast to hear it.

It's also worse trimmed out/up than in/down except at high RPMs.

 

[Faztbullet]

Check your gear oil,,,

 

[oldboat1]

My old 85 would wake up the neighborhood on muffs. In the water, there was nothing more at idle than a faint clicking sound. I think you may be describing a feature.