Yamaha F150 XB Low Frequency Knock

[ralphy670]

I noticed a low frequency knock on my F150 XB at idle after the engine warms up. The sound is really noticeable in person however you can hear it in the video with headphones on.
Dealer told me it sounds like exhaust but I dont think its normal.

Any thoughts?

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[mike_i]

I have the same motor. I can't hear anything other than the water from the pisser and the exhaust.Is there anyway you can reduce the noise of the water and record the audio closer to where you hear the noise?

 

[ralphy670]

I can try next time I am out. i have removed the cover and ran it as well and it appears to be coming from the starboard side. you mention that you can hear the exhaust, is it possible to describe it as that might be what I am hearing as well. The only exhaust coming out is through the relief port at the back and nothing through the prop. Does exhaust bubble inside the leg somewhere when at idle rpm