yamaha 225 exhaust

[catsnstripers]

I have a '05 225 yamaha. F225TXRD. This may be a silly question, but i am just curious. I'm just wondering if this is normal?? At times i notice this residue for my exhaust. I understand water does cover this at times and most of the run is due to water drain. Now granted it only shows up when i put the boat onto the trailer the boat will of coarse tilt up, submerging this port underwater. Also when myself and another stands on the back deck, it again submerges and a small film will appear... Just curious, here is a picture... Thank you for your help

Travis

[rodbolt17]

its an exhaust idle relief port, its a normal thing.
as long as its a dry carbon and not oily.

[catsnstripers]

I'm not sure if its oily or just wet from the water. Even with just being carbon, when it gets wet would it leave a small film/slick on the surface when water gets around it?