2004 15hp 4-stroke noise

[Dashunde]

I picked up a genuinely new condition 2004 15hp 4-stroke (F15ESHC) the other day, I doubt it has more than 10 hours on it.

It has a odd squeal/chirp/ringing noise that is identical to the one in the following you tube video (thats not my too-big-for-15hp boat in the video),
Mine is not as loud or consistent, but its the same sound.

https://www.youtube.com/watch?v=XsayvwRfYo8
The sound is really clear at 2:10 and 3:05 or thereabouts.

My F15 is on a little 14ft Lowe and it seems to run out fine othewise.

It'll also make the noise (quietly/intermittently) when its idling on the hose in the driveway.
It sounds like its coming from the upper timing belt area.

Anyone know what the noise is, what can be done about it, and whether I should be concerned about it in the first place?

[TownsendsFJR1300]

I had a high pitched squeal come and go at about 1,600 RPM's. Sounded like a squeaking bird in the background.

Mine turned out be using the wrong grease on the main lower unit drive shaft in the mid section(long shaft). There is a bushing (I don't know if yours even has it) and you HAVE to use Yamaha's Marine waterproof grease there. I had previously used marine wheel bearing grease, but that does not work more than a month or two...

Someone else will chime in BUT, if you know you have that mid shaft machined surface and a bushing in the mid section, without proper grease it'll make a similar noise.

Mine wasn't as bad as yours, but quite annoying..

Here's the part fisch for your engine; 2004 F15ESHC Yamaha Outboard Parts

[Dashunde]

Hi all, I clarified a few things in my first post.

The sound seems to be coming from the timing belt and gets louder as it warms up.
The belt is 10 years old, but has nearly no running time on it and isnt dry/cracking at all.
I suppose it wouldnt hurt to replace it anyway, in the meatime I have two questions:

Is the F15 a interference motor?
Is it a bad idea to use a light belt dressing on a timing belt?
(Mostly to verify the source of the noise and to quiet it for the remainder of this season.)