Adding a Fresh Water Cooling System

Canadian Runabout
A 1957 Greavette, a Canadian built runabout.

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”