Abstract: A method for controlling a marine engine uses a flow regulating valve in combination with a solenoid operated two position control valve to regulate the flow of cooling water through exhaust system components. Temperatures are measured at the components, such as within the cooling jacket of exhaust manifolds, and a microprocessor compares the measured temperatures to desired ranges. When the temperatures exceed upper limits, additional flow is directed from a pump to the exhaust system components. When the temperatures are below desired flow thresholds, the flow of the water in the pump is restricted in order to allow the exhaust system components to rise in temperature.

Abstract: A cooling system for a marine propulsion device provides a bypass loop around a cooling pump that allows the flow of cooling water through certain components to be reduced or increased as a function of the temperature of those components while causing a full flow of cooling water to flow through other selected heat emitting devices. Using this configuration of components and bypass conduits, the operating condition of the cooling water pump can be continually monitored, including the condition of its flexible vanes. By observing the effective cooling capacity of the system under conditions with the bypass valve open and closed, the effectiveness of the cooling water pump can be assessed and a suggestion of maintenance can be provided.

Abstract: A method for cooling a marine propulsion system directs a portion of a recirculating stream of cooling water to a first port of an exhaust manifold so that a cooling jacket of the exhaust manifold can be maintained in a filled condition. Water flows upwardly through the cooling jacket and exits through a port in the exhaust manifold back into the recirculating stream of cooling water that passes through a recirculation pump, the cooling passage of an engine, and a cavity of a thermostat housing.