Strange grease/oil appearing

[sea strike]

I have a 1996 c115 Yamaha outboard. After using for a day some strange thick grease appears on the intake behind the top carberator. I clean it off and it comes back again after the next run. Any common problem that this might be from? Thank you

[boats.net]

Only grease on top of engine is the grease around spark advance plate, may be melting and running down.