High pitch outboard engine noise

[Hooksetter]

I have a 2000 2-stroke 90 HP Johnson outboard that has developed a faint high pitched harmonic type noise when in gear at low RPMs. It is probably there at higher RPMs but masked by the engine noise. The engine runs great, and I don't think most people would notice the noise, but I do.

The water pump and shaft seal in the lower unit was replaced last year. There is a 3 week wait for mechanic, so I am trying to decide if I can continue to run it until a mechanic is available.

Anyone have any ideas on what the source of the noise might be?

[shakey doug]

You may have a singing prop try reshaping the tailing edge bit by bit, do not go at it to hard first off.

[Hooksetter]

Thanks Shakey.

This is the same prop that has been on the boat for many years and I don't see any noticeable difference in the blades. Is it possible that this could develop over time?
Will keep this in mind as I muddle through this one. Thanks again.

[shakey doug]

Yes it possible this can happen over time particularly with softer alloy props. If it is an alloy prop just rub blade tips with sandpaper this can be enough to fix it .