Abstract: An internal combustion engine includes at least one combustion chamber formed by at least a first member and a second member that moves relative to the first member. The second member is coupled to an output shaft such that movement of the second member causes the output shaft to rotate. The engine also includes a cooling system configured to circulate coolant into thermal communication with at least a portion of the engine. An induction system is also included for providing a fuel/air charge to the combustion chamber. The induction system includes a charge former configured to form the fuel/air charge and a mounting plate that is attached to the carburetor. The mounting plate includes a first coolant passage that is in communication with the cooling system.

Abstract: An outboard motor includes a power head, driveshaft housing and lower unit, and employs a cooling system to cool the driveshaft housing. Portions of the driveshaft housing experience substantial heat transfer from the exhaust gases that pass through the driveshaft housing. The driveshaft housing cooling system cools the heated portions of the driveshaft housing. The cooling system includes delivery pipes adapted to deliver water to the outer surface of each side of the driveshaft housing. The water is distributed to the housing outer surface in a manner to establish a substantially even flow across the surface so that heat is dissipated from the housing in order to prevent the housing from reaching very high temperatures.

Abstract: An internal combustion engine includes at least one combustion chamber formed by at least a first member and a second member that moves relative to the first member. The second member is coupled to an output shaft such that movement of the second member causes the output shaft to rotate. The engine also includes a cooling system configured to circulate coolant into thermal communication with at least a portion of the engine. An induction system is also included for providing a fuel/air charge to the combustion chamber. The induction system includes a charge former configured to form the fuel/air charge and a mounting plate that is attached to the carburetor. The mounting plate includes a first coolant passage that is in communication with the cooling system.

Abstract: Embodiments of four-cycle outboard motors having an improved exhaust system. The exhaust system includes an expansion chamber that is formed in the drive shaft housing of the outboard motor below an oil tank for the engine which is positioned therein. A water chamber is formed around the expansion chamber and the lower portion of the oil tank for cooling them. An above-the-water exhaust gas discharge is provided that communicates with the area above the water jacket.

Abstract: A protective cowling arrangement for an outboard motor that provides an atmospheric air inlet having a pair of openings disposed above the engine for permitting atmospheric air to flow into the protective cowling for engine combustion. One of these openings is disposed in part above components of the engine which should not be contacted by water and this opening is substantially smaller than the other opening. An engine cover is also affixed to the engine and obscures the smaller opening to afford further water protection.

Abstract: An air intake device for a marine propulsion engine that effectively separates water from the intake air and precludes that water from being swept back into the induction system for the engine. A plenum chamber is formed as a separate part of the air intake device and is connected to the carburetor through a transition portion that extends across the upper end of the plenum chamber. The plenum chamber is displaced forwardly of the carburetor so as to not interfere with it or restrict its size.