Abstract: Methods, assemblies and apparatuses are for forming a cooling jacket in a cast part of a marine engine, for example in a cylinder head for the marine engine. A cooling jacket core has a longitudinally elongated first portion that forms a first flow path for conveying cooling fluid through the cast part in a first direction and a longitudinally elongated second portion that forms an opposite, second flow path for conveying cooling fluid through the cast part in an opposite, second direction. At least one bridge integrally supports the first and second portions with respect to each other during casting. At least one plug is configured to fit in the cast part where the bridge was located so as to separate the first and second flow paths from each other while sealing the first and second flow paths from an opposite side of the cast part.

Abstract: Methods, assemblies and apparatuses are for forming a cooling jacket in a cast part of a marine engine, for example in a cylinder head for the marine engine. A cooling jacket core comprises a longitudinally elongated first portion that forms a first flow path for conveying cooling fluid through the cast part in a first direction and a longitudinally elongated second portion that forms an opposite, second flow path for conveying cooling fluid through the cast part in an opposite, second direction. At least one bridge integrally supports the first and second portions with respect to each other during casting. At least one plug is configured to fit in the cast part where the bridge was located so as to separate the first and second flow paths from each other while sealing the first and second flow paths from an opposite side of the cast part.

Abstract: An outboard marine engine comprises a vertically aligned bank of piston-cylinders; an intake camshaft that operates a plurality of intake valves for controlling inflow of air to the bank of piston-cylinders; an exhaust camshaft that operates a plurality of exhaust valves for controlling outflow of exhaust as from the bank of piston-cylinders; and a cam-to-cam connector that connects the intake camshaft to the exhaust camshaft such that rotation of one of the intake and exhaust camshafts causes rotation of the other of the intake and exhaust camshafts. The cam-to-cam connector is located vertically above a lowermost intake valve in the plurality of intake valves, vertically above a lowermost exhaust valve in the plurality of exhaust valves, vertically below an uppermost intake valve in the plurality of intake valves and vertically below an uppermost exhaust valve in the plurality of exhaust valves.

Abstract: An outboard marine engine comprises a vertically aligned bank of piston-cylinders; a camshaft that operates a plurality of valves for controlling flow of air with respect to the vertically aligned bank of piston-cylinders, the camshaft vertically extending between a lower camshaft end and an upper camshaft end; and a cam lobe at the upper camshaft end. Rotation of the camshaft causes the cam lobe to cam open an uppermost valve in the plurality of valves. A lubricant circuit extends through the camshaft and has a lubricant outlet located at the upper camshaft end. The lubricant outlet is configured to disperse lubricant onto the uppermost valve, which is located above an uppermost cam bearing bulkhead for the upper camshaft end.

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.

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: A marine engine is made with a head portion that includes an exhaust manifold that is formed as an integral part of the head portion during a lost foam casting procedure. The head portion comprises a plurality of combustion chambers in which each combustion chamber has at least one exhaust throat that connects the combustion chamber in fluid communication with at least one exhaust port. All of the exhaust ports connect associated combustion chambers in fluid communication with an exhaust manifold that is formed integrally within the head portion during the initial lost foam casting process. An exhaust outlet opening from the exhaust manifold is positioned above at least one exhaust port of at least one combustion chamber to form a water trap or stand pipe that inhibits water ingestion under certain adverse conditions. Water passages and oil passages are formed integrally within the head portion during the lost foam casting process.

Abstract: An engine for use in a marine propulsion system for use on a boat having a force balancer mechanism for off-setting the shaking force created by the reciprocating pistons. In a two-cylinder, four-stroke marine engine, a pair of reciprocating pistons move in unison within respective cylinders. The force balancer mechanism is mounted to the rotating crankshaft such that rotation of the crankshaft results in reciprocating movement of the balance weight in a direction opposite the pair of pistons. The balance weight of the force balancer mechanism is contained within a balance weight housing formed in the engine block. The weight of the balance weight and the distance of the balance weight from the axis of rotation of the crankshaft are selected to optimally reduce the amount of shaking force in the engine.

Abstract: The tilt mechanism (10) for a marine propulsion unit has a swivel bracket (14) pivotally attached to a transom bracket (11). A trim pin (20) is carried by a trim pin carrier (24) which is pivotally attached to the swivel bracket (14). The trim pin (20) travels in cam slots (19) which define two connected cam loops and acts as a ratchet with notches (21, 22, 23) in the cam slots (19) to establish trim and tilt positions for the propulsion unit. The two cam loops allow the propulsion unit to be returned to the uppermost position without dropping to the lowest position first. A moveable return cam (38) in the lower loop allows the operator to select the lowest trim position to which the unit will return.