Honda Giken Kogyo Kabushiki Kaisha

Hiroshi Kawamura

Hiroyuki Murata

Hiroyuki Yoshida

Yoshimi Watanabe

Mitsuharu Tanaka

Kouji Koishikawa

Kouichi Oka

Nobuo Haga

Takao Aihara

Sukehiro Yamaguchi

Chiharu Sohda

In an outboard motor including a centrifugal clutch system between the engine crankshaft and the drive shaft and including an exhaust pipe that has an outlet which is submerged under water in an operable state of the outboard motor, the exhaust pipe is provided with an exhaust vent which is positioned above water in an operable state of the outboard motor. Thus, when a reverse rotation takes place in the event of unsuccessful engine start, the exhaust vent allows atmospheric air to flow into the exhaust pipe so as to prevent the internal combustion engine from working as a suction pump and introducing water into the engine cylinder through the exhaust pipe.

Outboard Motor

In an outboard motor, a simple drain structure is provided which can drain the water that has entered the engine compartment while effectively preventing water from entering the engine compartment through the drain structure itself. A drain passage is formed in a peripheral portion of an engine mount member which, together with a part of an engine cover, constitutes a bottom of the engine compartment. A reed valve unit made of a resilient material and having a base portion and a valve portion is fittingly received by the side wall defining the drain passage of the mount member so that the valve portion normally closes the opening of the drain passage due to its own resiliency and bend to drain water when water accumulates in the drain passage.

Drain structure of an outboard motor

An outboard motor includes an exhaust emission control system which is arranged rationally and neatly in the housing of an outboard motor body, irrespective of various limitations on the outside shape of the housing. An oil pan disposed below an engine of the outboard motor has an oil holding portion, and an exhaust pipe is disposed vertically along a vertical wall portion of the oil holding portion. A catalytic converter is disposed in an intermediate portion of the exhaust pipe in confronted relation to the vertical wall portion. The catalytic converter has a particular shape in horizontal section which is greater in size in a first direction than in a second direction perpendicular to the first direction. A fresh-air delivery passage is provided for introducing fresh air into an exhaust passage disposed upstream of the exhaust pipe. The fresh-air delivery passage is connected at one end to the top plate of an intake box and includes a check valve disposed at an intermediate portion of the fresh-air passage. The check valve is adapted to open only when the pressure in the exhaust passage is less than the atmospheric pressure. The exhaust system is perfectly protected against a possible entry of water and an engine combustion failure and corrosion of the exhaust system resulting therefrom.

Outboard motor

An exhaust pipe for guiding an exhaust gas from an engine into an exhaust gas expansion chamber defined within an extension case is connected to a protrusion of an oil pan which is mounted on a lower surface of a mount case that supports the engine at its upper portion. A breathing bore is formed in an upper portion of the exhaust pipe, and an outer side of the breathing bore is covered with a shield plate. Therefore, water cannot enter the exhaust pipe through the breathing bore. A cooling-water supply pipe for introducing cooling water from a cooling-water pump into the engine is formed with a cooling-water ejection bore which is located at a position in which it is not opposed to the breathing bore. Therefore, even if cooling water is ejected through the cooling-water ejection bore to the exhaust pipe to cool the latter, the cooling water cannot enter the exhaust pipe.

Exhaust pipe structure in outboard engine system

An outboard engine arrangement comprises a transmission for shifting a speed change ratio at least at two stages of higher and lower speeds, the transmission being interposed between a crank shaft of an upper side engine and a drive shaft located coaxilly with the crank shaft for driving a lower side propeller and being contained within an oil pan for the engine, a vertically extending oil feed bore being provided to lubricate the transmission, and means being provided for permitting the oil feed bore to communicate with a bottom in a crank case of the engine.

Outboard engine arrangement

An outboard engine construction in which an engine is mounted at the upper end of an extension case provided with a stern bracket adapted to be clamped to a stern plate of a vessel and a gear case having a rotatable propeller is connected to the lower end of the extension case. A drive shaft connected to a crank shaft of the engine is housed within the extension case and a drives a gear assembly connected to the propeller. The extension case is constituted by a primary upper case portion and a selectively removable auxiliary lower case portion. A transmission is contained in the auxiliary case portion and is detachably interposed therewith between the drive shaft and the gear assembly.

Growing community of inventors

Wako, Japan

Hiroshi Kawamura