99 evinrude 50hp 4stroke, screech

[Rickfa]

Evinrude 50hp 4 stroke 1999, starts and runs ok makes a squeal like a bearing seizing, at higher rpms with muffs on, after running for 10-30 seconds, in gear and no prop,
reverse in gear no noise,, at rev limiter in neutral no noise, pull back to idle no noise, oil full, pp stream so so, no indication or warning lights, any ideas, thanks