Hi, i have a problem with My tohatsu 9.8 making a strange sound at a specific rpm, took it to the the local tohatsu workshop but they didnt find anything,
As was discussed ad nauseum 10 years ago, that sound happens on some MFS8/9.8 motors around 2200 RPM. It is a harmonic in the intake. It is not an indicator of anything wrong. Because the rest of the motor is so quiet... that is why the sound is heard.