Abstract: An internal combustion engine and a method of forming an internal combustion engine are for a marine propulsion device. A first engine casting defines a first flow passage configured to receive the exhaust gases from a piston-cylinder. A die cast second engine casting defines a second flow passage that is configured to receive the exhaust gases from the first flow passage and convey the exhaust gases to a catalyst. The second flow passage has an upstream first leg that is parallel to the first flow passage and a downstream second leg that is transversely oriented to the first leg. An inside corner is between the first and second legs. The second flow passage has an inlet end that is configured to receive exhaust gases from the first flow passage. The first flow passage has an outlet end that is configured to convey exhaust gases to the inlet end of the second flow passage.

Abstract: An outboard marine engine has an engine block; a crankcase on the engine block; a crankshaft disposed in the crankcase for rotation about a crankshaft axis; a cover on the crankcase; a bedplate disposed between the engine block and the cover, the bedplate having a plurality of bearings for supporting rotation of the crankshaft; and a cooling water jacket that extends parallel to the crankshaft axis along a radially outer portion of the plurality of bearings. The cooling water jacket carries cooling water for cooling the plurality of bearings and at least one oil drain-back area is located adjacent to the cooling water jacket. The at least one oil drain-back area drains oil from the crankcase.

Abstract: An outboard marine propulsion device comprises an internal combustion engine having a cylinder head and a cylinder block and an exhaust manifold that discharges exhaust gases from the engine towards a vertically elongated exhaust tube. The exhaust manifold has a plurality of inlet runners that receive the exhaust gases from the engine, and a vertically extending collecting passage that conveys the exhaust gases from the plurality of inlet runners upwardly to a bend that redirects the exhaust gases downwardly towards the exhaust tube. A cooling water jacket is on the exhaust manifold and conveys cooling water alongside the exhaust manifold. A catalyst housing is coupled to the exhaust manifold and a cooling water jacket is on the catalyst housing and carries cooling water alongside the catalyst housing. A catalyst is disposed in the catalyst housing.

Abstract: An outboard marine propulsion device comprises an internal combustion engine having a cylinder head and a cylinder block; and an exhaust manifold that discharges exhaust gases from the engine towards a vertically extending catalyst housing. The exhaust manifold has a plurality of horizontally extending inlet runners upwardly that receive the exhaust gases from the engine, and a vertically extending collecting passage that conveys the exhaust gases from the plurality of horizontally extending inlet runners to a bend that redirects the exhaust gases downwardly towards the catalyst housing.

Abstract: An outboard marine propulsion device comprises an internal combustion engine. At least one engine cooling passage conveys cooling water through the internal combustion engine. An exhaust manifold comprises a plurality of exhaust runners and an exhaust log. The plurality of exhaust runners axially conveys exhaust gases from the internal combustion engine to the exhaust log. A cooling jacket on the exhaust manifold comprises an exhaust log cooling jacket that conveys the cooling water along an outer surface of the exhaust log and a plurality of exhaust runner cooling passages that each axially convey the cooling water along an outer surface of a respective one of the plurality of exhaust runners from the exhaust log cooling jacket to the engine cooling passage.

Abstract: Systems and methods are for indicating oil level in an outboard motor to an operator. An outboard motor has an internal combustion engine that drains oil to a sump; a sensor that senses oil level in the sump; and an input device and an indicator on the outboard motor. Actuation of the input device causes the sensor to determine the oil level, and then the indicator to indicate to the oil level to the operator.

Abstract: Marine engine includes a cylinder block having first and second banks of cylinders that are disposed along a longitudinal axis and extend transversely with respect to each other in a V-shape so as to define a valley therebetween. A catalyst receptacle is disposed at least partially in the valley and contains at least one catalyst that treats exhaust gas from the marine engine. A conduit conveys the exhaust gas from the marine engine to the catalyst receptacle. The conduit receives the exhaust gas from the first and second banks of cylinders and conveys the exhaust gas to the catalyst receptacle. The conduit reverses direction only once with respect to the longitudinal axis.

Abstract: A cooling system for a marine engine is provided with various cooling channels which allow the advantageous removal of heat at different rates from different portions of the engine. A split flow of water is conducted through the cylinder head, in opposite directions, to individually cool the exhaust port and intake ports at different rates. This increases the velocity of coolant flow in the downward direction through the cylinder head to avoid the accumulation of air bubbles and the formation of air pockets that could otherwise cause hot spots within the cylinder head. A parallel coolant path is provided so that a certain quantity of water can bypass the engine block and avoid overcooling the cylinder walls.

Abstract: A marine propulsion system comprises an internal combustion engine, a cooling circuit carrying cooling fluid that cools the internal combustion engine, a sump holding oil that drains from the internal combustion engine, and a heat exchanger receiving the cooling fluid. The oil that drains from the internal combustion engine to the sump passes through and is cooled by the heat exchanger.

Abstract: A marine engine has an exhaust system comprising a cylinder block comprising first and second banks of cylinders that are disposed along a longitudinal axis and that extend transversely with respect to each other in a V-shape so as to define a valley there between. A catalyst receptacle is disposed in the valley and contains at least one catalyst that treats exhaust gas from the marine engine. An exhaust manifold conveys exhaust gas from the marine engine to the catalyst receptacle. The exhaust manifold has a first port receiving exhaust gas from the first bank of cylinders, a second port receiving exhaust gas from the second bank of cylinders, and a conduit conveying the exhaust gas from the first and second ports to the catalyst receptacle, wherein from the first and second ports to the catalyst receptacle, the conduit only reverses direction once with respect to the longitudinal axis.

Abstract: A cooling system for a marine engine has an elongated exhaust conduit comprising a first end receiving hot exhaust gas from the marine engine and a second end discharging the exhaust gas; and an elongated cooling water jacket extending adjacent to the exhaust conduit. The cooling water jacket receives raw cooling water at a location proximate to the second end of the exhaust conduit, conveys raw cooling water adjacent to the exhaust conduit to thereby cool the exhaust conduit and warm the raw cooling water, and thereafter discharges the warmed cooling water to cool the internal combustion engine.

Abstract: A cooling system for a marine engine is provided with various cooling channels which allow the advantageous removal of heat at different rates from different portions of the engine. A split flow of water is conducted through the cylinder head, in opposite directions, to individually cool the exhaust port and intake ports at different rates. This increases the velocity of coolant flow in the downward direction through the cylinder head to avoid the accumulation of air bubbles and the formation of air pockets that could otherwise cause hot spots within the cylinder head. A parallel coolant path is provided so that a certain quantity of water can bypass the engine block and avoid overcooling the cylinder walls.