Boat motors use the water they’re floating in to cool them. Some, like most outboards, have what’s called a “raw water” system. The water the boat is floating in circulates through the engine block, then exits with the exhaust. Most modern inboards have a “fresh water” or “indirect” cooling system. In this system, coolant like that in your automobile is pumped through a heat exchanger. The coolant is circulated through the engine block rather than the raw water itself. Continue reading “Adding a Fresh Water Cooling System”