Abstract: A marine propulsion device has an engine; an exhaust manifold for conveying exhaust gas from the engine; a cooling water jacket on the exhaust manifold, wherein a cooling water passage for conveying cooling water alongside the exhaust manifold is defined between the cooling water jacket and exhaust manifold; and a cooling water sprayer that sprays cooling water into the exhaust manifold. A manually serviceable cooling water strainer configured to strain cooling water supplied from the cooling water passage to the cooling water sprayer. The manually serviceable cooling water strainer can be manually coupled to and manually uncoupled from the marine propulsion device without use of a tool.

Abstract: An exhaust manifold is for an outboard motor having an internal combustion engine. The exhaust manifold has an exhaust conduit that conveys exhaust gas from the internal combustion, and a cooling jacket on the exhaust conduit. The cooling jacket defines a first cooling water passage that conveys cooling water in a first direction alongside the exhaust conduit, a second cooling water passage that conveys the cooling water from the first cooling water passage in an opposite, second direction alongside the exhaust conduit, and third cooling water passage that is separate from the first and second cooling water passages and conveys spent cooling water from the internal combustion engine to a thermostat.

Abstract: A marine propulsion device includes an internal combustion engine; an axially elongated exhaust conduit that conveys exhaust gas from the upstream internal combustion engine to a downstream outlet; a cooling water sprayer that is configured to spray a flow of cooling water radially outwardly toward an inner diameter of the axially elongated exhaust conduit; a temperature sensor located downstream of the cooling water sprayer and configured to sense temperature of the exhaust gas and cooling water; and a controller configured to identify a fault condition associated with the cooling water sprayer based on the temperature of the exhaust gas and cooling water.

Abstract: An open loop cooling water system is for a marine engine. A cooling water inlet receives cooling water from a body of water. A cooling water outlet discharges the cooling water back to the body of water. A cooling water circuit conveys cooling water from the cooling water inlet, through the marine engine, and to the cooling water outlet. A cooling water pump that pumps cooling water from upstream to downstream through the cooling water circuit. A recirculation pump that is located in the cooling water circuit downstream of at least one component of the marine engine and upstream of the cooling water outlet. The recirculation pump is configured to pump cooling water from downstream of the marine engine back into the cooling water circuit upstream of the marine engine. Methods are for cooling a marine engine using an open loop cooling system.