How is a 1976 Johnson outboard cooled?

Cooling water is drawn into the water pump through the inlet screen on the gearcase. This water then travels to the powerhead via a copper tube. It then circulates the water passages within the engine block, thereby, cooling the powerhead. At this point, most of the cooling water is expelled out through the exhaust, providing additional cooling to the exhaust housing and tuner. On most outboards a small amount of this cooling water will also exit via the "tell-tale" hose, added for visual pump operation. Many outboards also incorporate a thermostat into the cooling system to regulate powerhead temprature, as well as pressure relief or poppett valves.