Abstract: An outboard motor includes a cowling enclosing an engine, an ambient air intake defined by the cowling, and an intake passage introducing ambient air taken through the ambient air intake to the engine. The intake passage extends out of and above a top section of the cowling. An inlet portion of the intake passage communicates with the ambient air intake, and an outlet portion thereof communicates with an air inlet leading to a silencer of the engine the air inlet is positioned vertically higher than the intake passage inlet portion.

Abstract: An outboard motor includes an engine having an air intake device. The cowling has an engine room in which the engine is disposed. One or more air intake openings are formed through the cowling. A water separation device is included in the cowling interposed between the air intake opening and the engine room. A first intake passage of the water separator communicates with the ambient air opening. A second intake passage communicates with an upper portion of the first intake passage. If a large flow of water enters the first intake passage through the air opening, such water flows out of the cowling through another opening and/or into a holding chamber formed in the cowling so as not to flow into the second intake passage.

Abstract: An outboard motor includes a cowling enclosing an engine, an ambient air intake defined by the cowling, and an intake passage introducing ambient air taken through the ambient air intake to the engine. The intake passage extends out of and above a top section of the cowling. An inlet portion of the intake passage communicates with the ambient air intake, and an outlet portion thereof communicates with an air inlet leading to a silencer of the engine the air inlet is positioned vertically higher than the intake passage inlet portion.

Abstract: An outboard motor includes an engine having an air intake device. The cowling has an engine room in which the engine is disposed. One or more air intake openings are formed through the cowling. A water separation device is included in the cowling interposed between the air intake opening and the engine room. A first intake passage of the water separator communicates with the ambient air opening. A second intake passage communicates with an upper portion of the first intake passage. If a large flow of water enters the first intake passage through the air opening, such water flows out of the cowling through another opening and/or into a holding chamber formed in the cowling so as not to flow into the second intake passage.

Abstract: An outboard motor includes an engine having an air intake device. A cowling has an internal space in which the engine is disposed and an air intake opening through which ambient air is introduced into the internal space. The internal space defines an air intake passage connecting the air intake opening of the cowling to the air intake device of the engine. An air/water separator is disposed within the air intake passage for separating water from the air. The air/water separator has a relative large volume so as to temporarily hold water from a sudden flow of water that may flow into the cowling air intake. Water accumulated in the separator is drained from the cowling.

Abstract: A crankcase ventilation system is provided for an outboard motor having a cowling and a water propulsion device, an internal combustion engine positioned in the cowling and arranged to propel the water propulsion device. The engine having at least one combustion chamber, a crankcase chamber into which blow-by air and fuel from the combustion chamber passes, a lubricating system including an oil filter and an ignition system including an ignition element for initiating combustion in said combustion chamber. The crankcase ventilation system includes an air intake member defining an intake chamber, at least one air intake port providing a source of air for the engine communicating with the intake chamber and an output port in fluid communication with the intake chamber for delivery of the air to the engine from the intake chamber. At least one blow-by port directs blow-by mixture from the crankcase chamber into the intake chamber at a point on the air intake member between the intake port and the output port.

Abstract: An outboard motor embodying a four-cycle internal combustion engine having a decompression device for automatically reducing the compression ratio to assist in pull starting. The decompression device is mounted and operated through one end of the cam shaft and thus facilitates modification of engines so as to incorporate this feature or not incorporate the feature. The construction also facilitates lubrication of a centrifugal mechanism that actuates the decompression device.

Abstract: An intake manifold for an engine powering a water propulsion device of an outboard motor is disclosed. The engine has first and second combustion chambers and an intake system for delivering a fuel and air charge to each combustion chamber. The intake system includes a first intake passage leading through the engine to the first combustion chamber and a second intake passage leading through the engine to the second combustion chamber, the first intake passage positioned vertically above the second intake passage. The intake manifold is arranged to deliver equal amounts of fuel to the first and second intake passages and includes a main passage extending along a first axis. A first branch defines a passage leading the main passage to the first intake passage, and a second branch defines a passage leading from said main passage to the second intake passage.

Abstract: An arrangement for an engine positioned in a cowling of an outboard motor and having an output shaft arranged to drive a water propulsion device of the motor is disclosed. The engine has a first end and a second end and a centerline passing through the ends, at least one combustion chamber, an intake system positioned along a first side of the engine for delivering air to the combustion chamber, a lubricating system including an oil filter for delivering lubricant to the engine and an ignition system including an ignition coil for charging an ignition element corresponding to the combustion chamber. The ignition coil and oil filter are positioned along a second side of the engine opposite the intake system and arranged to reduce the transfer of heat from the filter to the coil, with the oil filter having an outermost portion which is positioned outwardly of the engine between the centerline and a second line which extends parallel to the centerline and passes through an outermost portion of the ignition coil.

Abstract: An outboard motor embodying a four-cycle internal combustion engine having a decompression device for automatically reducing the compression ratio to assist in pull starting. The decompression device is mounted and operated through one end of the cam shaft and thus facilitates modification of engines so as to incorporate this feature or not incorporate the feature. The construction also facilitates lubrication of a centrifugal mechanism that actuates the decompression device.

Abstract: A ventilation system is provided to vent blow-by gases from a crankcase of an internal combustion engine and to deliver the blow-by gases back to the combustion chambers of the engine for eventual expulsion through the engine exhaust system. The ventilation system includes a lubricant separator located on the side of a cylinder block of the engine. The lubricant separator desirably lies beneath a charge former of the engine at a location which does not increase the overall girth of the engine. The ventilation system also desirably includes a secondary lubricant separator integrated into an intake air device which communicates with the charge former. Both the first and second lubricant separators deliver lubricant, which is separated from the vented blow-by gases back to a reservoir of a lubrication system. The blow-by gases that are vented through the first and second lubricant separators are delivered to the charge former through the intake air device.

Abstract: An engine of an outboard motor includes an improved induction system, including an intake silencer mounted to a plurality of induction pipes. The intake silencer includes a first and second expansion chamber separated by a wall. The wall includes an aperture for communicating the first and second expansion chambers. A filter element is provided for the aperture for preventing debris from entering the second expansion chamber and induction pipes. The induction pipes are integrally formed in an induction pipe casting. The induction pipe casting and air intake silencer deliver air to a carburetor assembly. The induction pipe casting and carburetor assembly are sealingly engaged through a seal plate and plurality of seals disposed between the induction pipe casting and carburetor assembly for providing an air-tight seal therebetween.