Yamaha 8HP 4 Stroke Whine/Rattle Noise

Hi There,

I have a 2001 Yamaha 8HP 4 Stroke that makes a whine or rattle when the throttle is between 5-15%. It has been this way since I have owned it which has been about 5 years.

Here is a video of the noise https://youtu.be/yLnkdZUhfCc
If anyone has any ideas what could be wrong I would love to hear them!

Thanks

If gun to my head..I'd say gear whine..it does start out at the beginning low in pitch and rises with rpm. Might be cam chain if it uses one. But I'd say the lower gears might not have been properly set in the vary beginning. I doubt it uses straight cut bevel gears...they can be noisy even when set properly.

What happens to that sound when in neutral..

Years..and I mean years ago one would put fine saw dust in an automobiles rear gear box before sale to quiet down worn or maladjusted gear sets.. Not at all suggesting that cure...just a fun fact :shock:

here is my brothers Sea Ray that made the same squealing noise as yours.
just before the outdrive bearings melted and disintegrated



.

Thanks Sinkingfast,

I will check neutral tonight, however I'm quite sure there is no noise.

Johnny, I hope my Yamaha does not suffer the same fate as your brothers Sea Ray.

Thanks again

Seen plenty of F9.9's make noise too. Pull the lower unit drain bolt and inspect for metal. Hopefully you won't find any.