Abstract: An outboard motor includes a multi-cylinder engine which includes cylinders longitudinally oriented and vertically paralleled in a cylinder block, a cylinder head arranged at a rearward position of the cylinder blocks, and a crankcase arranged at a forward position of the cylinder block, the cylinder head having an outlet of an exhaust port at one side thereof. An exhaust system for the outboard motor includes an exhaust manifold which communicates the outlet of the exhaust port with an exhaust outlet opening, the exhaust manifold including a first exhaust gas passage extending in a vertical direction for gathering exhaust gas discharged from the outlet of each exhaust port and a second exhaust gas passage extending in a vertical direction adjacently to the first exhaust gas passage, and a catalyst unit is provided on the way of the second exhaust gas passage.

Abstract: An outboard motor includes a multi-cylinder engine which includes cylinders longitudinally oriented and vertically paralleled in a cylinder block, a cylinder head arranged at a rearward position of the cylinder blocks, and a crankcase arranged at a forward position of the cylinder block, the cylinder head having an outlet of an exhaust port at one side thereof. An exhaust system for the outboard motor includes an exhaust manifold which communicates the outlet of the exhaust port with an exhaust outlet opening, the exhaust manifold including a first exhaust gas passage extending in a vertical direction for gathering exhaust gas discharged from the outlet of each exhaust port and a second exhaust gas passage extending in a vertical direction adjacently to the first exhaust gas passage, and a catalyst unit is provided on the way of the second exhaust gas passage.

Abstract: A shift operation control system for an outboard motor, which is capable of reducing a load acting on a shift operation lever during a shift operation and a shock occurring during the shift operation, to thereby facilitate the shift operation. The shift operation by the shift operation lever (21) is continuously detected by a shift position detector (24), and when an early stage of the shift operation from the forward position to the neutral position or from the reverse position to the neutral position is detected and at the same time the engine speed at the detection is not less than a predetermined value, engine output reduction control is carried out, and when the shift position detector (24) detects that the shift position has been switched to the neutral position, the engine output reduction control is canceled.

Abstract: A shift operation control system for an outboard motor, which is capable of reducing load acting on a shift operation lever during a shift operation and a shock occurring during the shift operation, to thereby Facilitate the shift operation. The shift operation by the shift operation lever 21 is continuously detected by a shift position detector 24, and when an early stage of the shift operation from the forward position to the neutral position or from the reverse position to the neutral position is detected and at the same time the engine speed at the detection is not less than a predetermined value, engine output reduction control is carried out, and when the shift position detector 24 detects that the shift position has been switched to the neutral position, the engine output reduction control is canceled.

Abstract: An outboard motor includes a vertical multi-cylinder engine, a fly-wheel magneto device, a partition plate, and a ventilation fan. The vertical multi-cylinder engine is disposed in an engine cover and comprises a crank case and a crank shaft, the crank shaft being rotatably disposed and protruding upward from the crank case. The fly-wheel magneto device is disposed on the protruding portion of the crank shaft. The partition plate is disposed in the engine cover and partitions the inside of the engine cover into an engine air-inlet space and a space including a heat-generating source, the engine air-inlet space being disposed at the upper portion of the engine cover, and the space including a heat-generating source being disposed at the lower portion of the engine cover. The ventilation fan is disposed in the lower space below the partition plate.

Abstract: An outboard motor includes an engine, an engine holder disposed below the engine, a drive shaft housing which is disposed below the engine holder, an intake device including an intake manifold disposed to a side surface of the engine, a lubricant supply device for supplying lubricant oil to the engine, an oil filter disposed below the intake manifold, and an oil cooler arranged below the intake manifold and between the engine and the oil filter. The oil cooler includes a casing and a cooler body disposed inside the casing, and the casing is formed with a cooling water flowing-in union and a cooling water flowing-out union disposed in correspondence with the cooling water flowing-in union.

Abstract: An outboard motor includes a vertical multi-cylinder engine, a fly-wheel magneto device, a partition plate, and a ventilation fan. The vertical multi-cylinder engine is disposed in an engine cover and comprises a crank case and a crank shaft, the crank shaft being rotatably disposed and protruding upward from the crank case. The fly-wheel magneto device is disposed on the protruding portion of the crank shaft. The partition plate is disposed in the engine cover and partitions the inside of the engine cover into an engine air-inlet space and a space including a heat-generating source, the engine air-inlet space being disposed at the upper portion of the engine cover, and the space including a heat-generating source being disposed at the lower portion of the engine cover. The ventilation fan is disposed in the lower space below the partition plate.

Abstract: A tilt-up handle for an outboard motor is placed in the upper rear portion of an engine cover accommodating an engine and has an outside-air inlet opening rearwardly in the boat traveling direction. The outside-air inlet protrudes rearwardly in the boat traveling direction from a rear wall of the engine cover so as to be substantially aligned with an imaginary vertical line overlapping with the rear wall of the engine cover when the outboard motor is viewed in profile. The tilt-up handle prevents moisture from entering and allows outside air to enter an engine cover without compromising air intake.

Abstract: An outboard motor includes an engine, an engine holder disposed below the engine, a drive shaft housing which is disposed below the engine holder, an intake device including an intake manifold disposed to a side surface of the engine, a lubricant supply device for supplying lubricant oil to the engine, an oil filter disposed below the intake manifold, and an oil cooler arranged below the intake manifold and between the engine and the oil filter. The oil cooler comprises a casing and a cooler body disposed inside the casing, and the casing is formed with a cooling water flowing-in union and a cooling water flowing-out union disposed in correspondence with the cooling water flowing-in union.

Abstract: A tilt-up handle for an outboard motor is placed in the upper rear portion of an engine cover accommodating an engine and has an outside-air inlet opening rearwardly in the boat traveling direction. The outside-air inlet protrudes rearwardly in the boat traveling direction from a rear wall of the engine cover so as to be substantially aligned with an imaginary vertical line overlapping with the rear wall of the engine cover when the outboard motor is viewed in profile. The tilt-up handle prevents moisture from entering and allows outside air to enter an engine cover without compromising air intake.

Abstract: A fuel injection control device for outboard motors optimizes the air-fuel ratio when trim is applied to the outboard motor, especially those with two-cycle engines. In such an outboard motor, engine speed, throttle setting, engine boost pressure, engine temperature, intake air temperature, and/or other variables are detected and a basic fuel injection volume determined. Fuel is supplied to each of the engine's cylinders according to the detected values. A trim angle detecting means is used to indicate trim angle. During low-speed operation, the trim angle is detected, and the magnitude of a change in the trim angle is calculated. The magnitude of the change in the trim angle is used to estimate the residual fuel volume within the engine. The estimated value is used to apply correction to the basic fuel injection volume following the change in the trim angle. As a result, during low-speed operation, an optimal air-to-fuel ratio can be obtained when the trim of the outboard device is changed.

Abstract: In an outboard motor having a fuel-injected two-cycle engine, engine speed, throttle setting, engine temperature and/or other variables are detected and a basic fuel injection volume determined. Fuel is supplied to each of the engine's cylinders according to the detected values. When the engine is operating at a high speed, trim angle and vessel speed are detected. The trim angle and vessel speed are used to correct the basic fuel injection volume determined before high speed operation of the engine is detected.

Abstract: In an outboard motor having a fuel-injected two-cycle engine, engine speed, throttle setting, engine boost pressure, and/or other variables are detected and a basic fuel injection volume determined. Fuel is supplied to each of the engine's cylinders according to the detected values. When the engine is stopped, information about the operating conditions of the engine before the engine was stopped are saved in a memory of a controller. These saved values represent the residual fuel volume left in the engine's cylinders at a subsequent start-up of the engine. The saved values are used to correct the basic fuel injection volume determined at start-up by the controller.