Abstract: The present invention, in one aspect, is a cooling system for a marine engine and includes cylinder cooling jackets, cylinder head cooling jackets, and thermostatic and pressure controls which facilitate safely operating the engine with low water flow rates. In one specific embodiment, the cooling system is employed in a marine engine including a V-type cylinder block with two cylinder banks and a valley between the banks. Each cylinder bank includes a plurality of cylinder bores (e.g., each cylinder bank includes three cylinder bores in a six cylinder engine), and respective exhaust ducts extend from and are in flow communication with each cylinder bore. Respective coolant flow paths extend from the valley to a section of each cylinder bore water jacket adjacent each cylinder exhaust duct. Specifically, water is provided from the valley to adjacent each exhaust duct in the cylinder banks. Each cylinder bore water jacket includes an outlet at an upper portion of each said cylinder bank.