Yamaha Marine Kabushiki Kaisha

Yamaha Hatsudoki Kabushiki Kaisha

Kentaro Kameoka

Masanori Takahashi

Kimitaka Saruwatari

Yoshibumi Iwata

Satoshi Miyazaki

An engine body of the multiple-cylinder engine for an outboard motor can include a crankcase for supporting a crankshaft whose axis extends vertically, and plural cylinders that are vertically arranged in line, each cylinder horizontally extending outward from the crankcase, and each cylinder having a respective exhaust port formed in a cylinder head. There are can be provided plural exhaust passages, each passage extending from the downstream end of the exhaust port, each passage communicating with the exhaust port and expansion chambers. Each expansion chamber can communicate with the extending end of the exhaust passage.

Multiple-cylinder engine for outboard motor

An outboard motor can include a case that extends longitudinally and can be supported on a hull of a boat. An engine can be supported on the upper surface side of the case and a cowling can be supported on the upper end portion of the case for covering the engine from the outside. An idle exhaust passage can be formed to discharge exhaust produced during idling of the engine to the atmosphere from the inside of the case. An expansion chamber can be formed at a midway portion of the idle exhaust passage. The downstream end of the idle exhaust passage can serve as an idle exhaust port that is open to the atmosphere. A plurality of such idle exhaust ports can be formed.

Idle exhaust structure for outboard motor

An engine for an outboard motor is provided that can include a crankcase having a crankcase chamber, a cam chamber, and an oil pan disposed below the crankcase. The engine can also include a crank chamber oil-return passage through which lubricating oil can be returned from the crank chamber to the oil pan. Further, the engine can include a cam chamber oil-return passage through which lubricating oil can be returned from the cam chamber to the oil pan. Finally, the engine can also include a gas passage to provide communication between the crank chamber, the cam chamber, and the oil pan in order to allow passage of blow-by gas without substantial interference with the movement of the lubricating oil.

Four-stroke engine for an outboard motor

An outboard motorhas a cowlingof a two-piece structure including a top cowland a bottom cowl. Mating portions of the top and bottom cowls include a watertight seal. A first, horizontally-directed sealing portion is not visible from outside the cowling. A second, vertically-directed sealing portion is positioned inwardly from the first sealing portion. In some embodiments, an elongate rib depends from the top cowl generally into the bottom cowl. In other embodiments, the second sealing portion is positioned generally above the first sealing portion.

Outboard motor having a cowling

An outboard motor has a cowling comprising a top cowl that is removably engagable with a bottom cowl. A mating portion of the top cowl and the bottom cowl is sealed when the top and bottom cowls are engaged so as to prevent or inhibit water from entering the cowling through the mating portion. A splash-proof rib portion is attached to an inner face of the top cowl and extends downwardly preferably around the entire periphery of the top cowl. The depending rib portion is disposed inside of the upper end of the bottom cowl when the top cowl is mounted on the bottom cowl.

Outboard motor

A lubrication system is provided that allows delivery, and preferably regulated delivery, of lubricant to a coupling between a crankshaft and the driveshaft of, for example, an outboard motor. The lubrication system includes a passageway through which lubricant flows, and preferably a flow restrictor regulates the amount of lubricant delivered through the passageway. In one mode, the passageway is generally formed vertically through the central axis of a vertically oriented crankshaft and extends between the crankcase chamber and the coupling. Lubricant, such as crankcase oil, is able to flow through the passageway and onto the coupling. One or more seals preferably inhibit lubricant from flowing beyond the coupling.

Growing community of inventors

Shizuoka-ken, Japan

Kentaro Kameoka