Re: Mercury 8hp 2 stroke exhaust
Up at the top is usually exhaust relief ports. They are below the cowling on the rear of the engine at the top of the mid section. Usually 2 holes either round or rectangular. Purpose it to allow exhaust gasses to exit the engine without having to fight water pressure when the boat is at rest and the regular exhaust is several inches below the water line. Sometimes water/mist will come out with the gasses. At WOT there is usually a large volume of water that exits them....on some engines.
HTH,
Mark