Looking from the back of the ski, the cooling line in the middle of the hull (from the pump) goes to the left hand side of the head. The line on the left, goes to the right side of the head. The pump is always your feed, and the outlet is just that. Again, this is if you were standing behind the ski looking. The lines cross to help make it easier. Or, the line with the T fitting going to your waterbox goes to the opposite side of the exhaust sys and carbs, which comes from the pump.