Abstract: An outboard motor includes an engine holder, an engine installed above the engine holder, an intake apparatus disposed on one side of the engine, and an electric equipment box and an exhaust apparatus both disposed on another side of the engine. The intake apparatus comprises a throttle body installed in a front portion of the engine, a silencer operatively connected to an upstream side of the throttle body, a surge tank disposed on one side of the engine, and an intake manifold operatively connected to the surge tank. The silencer extends around a front side of the engine towards the exhaust apparatus. The silencer is provided with an upstream end portion to which an intake port is formed to open rearward. The upstream end portion may be fixed to a wall portion of the electric equipment box and the upstream end portion of the silencer has a lower surface to which an intake port is formed so that it opens downward.

Abstract: An outboard motor includes an engine holder, an engine disposed above the engine holder and the engine includes a cylinder block provided with a plurality of cylinders, a cylinder head disposed behind the cylinder block and a crankcase, a cam chain case through which said engine is mounted on the engine holder, and an exhaust apparatus operatively connected to the cylinder head. The exhaust apparatus includes an exhaust passage formed to the cam chain case, an exhaust manifold connected to the cylinder head, a water jacket formed to the exhaust manifold and another water jacket formed to the exhaust passage. The exhaust passage is formed at a portion near a central portion of the engine having most wide width in association with a lower end portion of the exhaust manifold.

Abstract: An outboard motor is equipped with an engine, an engine holder, an oil pan disposed below the engine in a state of the outboard motor being mounted to a hull, a water pump disposed below the oil pan, and a cooling water passage structure. The cooling water passage structure includes a vertical cooling water passage vertically passing through inside the oil pan and communicated with the side of the engine, a lateral cooling water passage extending in a lateral direction along a bottom surface of the oil pan, a cooling water supply pipe extending upward from the water pump and connected to a side of the engine, and a water pressure relief valve provided for the lateral cooling water passage for controlling a pressure increasing of the cooling water. The lateral cooling water passage has one end communicated with a lower end of the vertical cooling water passage and has another one end to which an upper end of the cooling water supply pipe is connected.

Abstract: An outboard motor includes an engine holder, an engine disposed above the engine holder in an installed state of the outboard motor, a flywheel magnet device disposed above the engine, an oil filter disposed on a side portion of the engine, an electric equipment box, an air suction device, an exhaust device and a fuel supply device, these electric equipment box, suction device, exhaust device and fuel supply device being arranged around the engine, and an engine cover covering the engine. The air suction device is composed of a throttle body, a surge tank and an intake manifold including a plurality of branch members extending from the surge tank, the intake manifold is disposed vertically, in the installed state, on one side of the engine so that the intake manifold is located between the flywheel magnet device and the oil filter as viewed from a side portion thereof and the intake manifold has at least a portion superposed on the flywheel magnet device and the oil filter as viewed in a plan view.

Abstract: An outboard motor comprises, in an installed or mounted state, an engine holder, an engine located to an upper portion of the engine holder, a drive shaft housing located to a lower portion of the engine holder for housing a drive shaft extending downward from the engine, and an oil pan formed to the engine holder, the oil pan being provided with a wall section to which steering brackets are secured through upper mounts. A first seal member is disposed at a mating surface portion of an upper surface of the drive shaft housing and a lower surface of the oil pan and a second seal member is disposed at a mating surface of an upper surface of the oil pan and a lower surface of the engine to thereby expose the drive shaft between the first and second seal members.