Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine and a transmission being selectively changeable in gear position to establish speeds including at least a first speed and a second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, it is determined whether acceleration is instructed to the engine when the second speed is established and operation of the engine is controlled to increase a fuel amount to be supplied to the engine when detected engine speed is greater than a predetermined speed, thereby improving the performance immediately after acceleration is started.

Abstract: An outboard motor mounted on a stern of a boat is provided with a transmission and an oil pump. The transmission has a first-speed and second-speed gears, a first-speed gear clutch made of a mechanical dog clutch and a second-speed gear clutch made of a hydraulic clutch each adapted to engage the first and second-speed gears on a power transmission shaft, and a first-speed gear shift actuator adapted to couple the first-speed gear clutch with the first-speed gear. In the transmission, a first speed is established when the first-speed gear is engaged on the power transmission shaft and a second speed is established when the second-speed gear is engaged on the power transmission shaft while the first speed has been established such that power of the engine is transmitted to the propeller through the established speed.

Abstract: An outboard engine unit includes a water pump disposed on a lower end portion of an input shaft of a transmission, and left and right cooling water feeding passages interconnecting the water pump and a cooling water inlet of an engine. The left and right cooling water feeding passages are disposed around a plurality of transmission gears disposed on the input shaft of the transmission. A cooling water drawn by the water pump is guided through the left and right cooling water feeding passages to the cooling water inlet.

Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine and transmission, it is configured to determine whether acceleration is instructed to the engine by an operator when the gear position is the second speed, detect a slip ratio of a propeller based on theoretical velocity and actual velocity of a boat, control a throttle opening to suppress increase in the slip ratio when the acceleration is determined to be instructed, and change the gear position from the second speed to the first speed when the slip ratio is equal to or less than a first predetermined value and the change amount of the slip ratio is equal to or less than a prescribed value. With this, it becomes possible to appropriately control operation of the engine and the transmission during acceleration, thereby improving the acceleration performance of immediately after acceleration start.

Abstract: A dog clutch mechanism incorporated in an outboard motor includes a sliding clutch dog member splined to a propeller shaft and having recesses on each end face thereof, and a row of gear teeth formed on an end face of each of a pair of driven gears rotatably mounted on the propeller shaft. Each of the recesses has a bottom surface stepped to provide a corner edge at a stepped portion thereof. Each of the gear teeth has a beveled surface formed at a rear edge as viewed from a rotating direction of the driven gear. When the gear teeth are in mesh with the recesses of the clutch dog member, the corner edge of the stepped bottom surface of each recess is in contact with the beveled surface of the mating gear tooth.

Abstract: An outboard engine unit, where a drive shaft is connected to an engine and rotatably supported in a drive shaft chamber via a bearing and where a gear mechanism for transmitting rotation of the drive shaft to a propeller shaft is accommodated in a gear chamber, includes: a lubricant circulation section for returning lubricant oil, having lubricated the bearing, back to the gear chamber; an oil storage chamber for receiving the lubricant oil having lubricated the bearing; and a return passage communicating the oil storage chamber with the gear chamber. The lubricant oil guided to the oil storage chamber is returned back to the gear chamber via the return passage.

Abstract: In an apparatus for controlling operation of an outboard motor having an engine to power a propeller, a transmission being selectively changeable in gear position to establish speeds including a first speed and second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, and a trim angle regulation mechanism regulating a trim angle through trim-up/down operation, the transmission is controlled to change the gear position from the second speed to the first speed when the second speed is selected and a throttle opening change amount is at or above a predetermined value; and the trim angle regulation mechanism is operated to start the trim-up operation based on engine speed. With this, the transmission can be appropriately controlled to suppress the decrease in boat speed caused by change of gear position, thereby mitigating an unnatural feel given to the operator.

Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine to power a propeller, and a transmission being selectively changeable in gear position to establish speeds including a first speed and a second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, engine speed is detected, it is determined whether acceleration is instructed when the second speed is established, and operation of the transmission is controlled to change the gear position from the second speed to the first speed when the acceleration is determined to be instructed, and then change back the gear position from the first speed to the second speed based on the detected engine speed, thereby enabling to control the transmission optimally.

Abstract: An outboard engine unit includes a water pump disposed on a lower end portion of an input shaft of a transmission, and left and right cooling water feeding passages interconnecting the water pump and a cooling water inlet of an engine. The left and right cooling water feeding passages are disposed around a plurality of transmission gears disposed on the input shaft of the transmission. A cooling water drawn by the water pump is guided through the left and right cooling water feeding passages to the cooling water inlet.

Abstract: An outboard motor mounted on a stern of a boat is provided with a transmission and an oil pump. The transmission has a first-speed and second-speed gears, a first-speed gear clutch made of a mechanical dog clutch and a second-speed gear clutch made of a hydraulic clutch each adapted to engage the first and second-speed gears on a power transmission shaft, and a first-speed gear shift actuator adapted to couple the first-speed gear clutch with the first-speed gear. In the transmission, a first speed is established when the first-speed gear is engaged on the power transmission shaft and a second speed is established when the second-speed gear is engaged on the power transmission shaft while the first speed has been established such that power of the engine is transmitted to the propeller through the established speed.

Abstract: An outboard engine unit, where a drive shaft is connected to an engine and rotatably supported in a drive shaft chamber via a bearing and where a gear mechanism for transmitting rotation of the drive shaft to a propeller shaft is accommodated in a gear chamber, includes: a lubricant circulation section for returning lubricant oil, having lubricated the bearing, back to the gear chamber; an oil storage chamber for receiving the lubricant oil having lubricated the bearing; and a return passage communicating the oil storage chamber with the gear chamber. The lubricant oil guided to the oil storage chamber is returned back to the gear chamber via the return passage.

Abstract: An outboard motor includes a transmission mechanism mounted between an output shaft of an engine and a propeller drive shaft. The transmission mechanism includes a clutch. An oil pump for generating a hydraulic pressure so as to switch the clutch is disposed underneath a lowermost one of transmission gears closely thereto. An oil pan is disposed underneath the oil pump and is placed inside an exhaust channel of a gear case.

Abstract: A clutch detent mechanism for an outboard motor includes a ball movable with a clutch dog member, a ball retainer member provided in a propeller shaft for retaining the ball in a predetermined position, and a compression coil spring acting on the ball to resiliently force the ball against the ball retainer member. The ball retainer member has a recessed portion for receiving therein the ball to thereby retain the clutch dog member in a neutral position, a front tapered portion provided on one side of the recessed portion for retaining the ball in a position to keep the clutch dog member in a forward shift position, and a rear tapered portion provided on the other side of the recessed portion for retaining the ball in a position to keep the clutch dog member in a reverse shift position.

Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine and transmission, it is configured to determine whether acceleration is instructed to the engine by an operator when the gear position is the second speed, detect a slip ratio of a propeller based on theoretical velocity and actual velocity of a boat, control a throttle opening to suppress increase in the slip ratio when the acceleration is determined to be instructed, and change the gear position from the second speed to the first speed when the slip ratio is equal to or less than a first predetermined value and the change amount of the slip ratio is equal to or less than a prescribed value. With this, it becomes possible to appropriately control operation of the engine and the transmission during acceleration, thereby improving the acceleration performance of immediately after acceleration start.

Abstract: In an apparatus for controlling operation of an outboard motor having an engine to power a propeller, a transmission being selectively changeable in gear position to establish speeds including a first speed and second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, and a trim angle regulation mechanism regulating a trim angle through trim-up/down operation, the transmission is controlled to change the gear position from the second speed to the first speed when the second speed is selected and a throttle opening change amount is at or above a predetermined value; and the trim angle regulation mechanism is operated to start the trim-up operation based on engine speed. With this, the transmission can be appropriately controlled to suppress the decrease in boat speed caused by change of gear position, thereby mitigating an unnatural feel given to the operator.

Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine to power a propeller, and a transmission being selectively changeable in gear position to establish speeds including a first speed and a second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, engine speed is detected, it is determined whether acceleration is instructed when the second speed is established, and operation of the transmission is controlled to change the gear position from the second speed to the first speed when the acceleration is determined to be instructed, and then change back the gear position from the first speed to the second speed based on the detected engine speed, thereby enabling to control the transmission optimally.

Abstract: In an apparatus for controlling operation of an outboard motor having an internal combustion engine and a transmission being selectively changeable in gear position to establish speeds including at least a first speed and a second speed and transmitting power of the engine to the propeller with a gear ratio determined by established speed, it is determined whether acceleration is instructed to the engine when the second speed is established and operation of the engine is controlled to increase a fuel amount to be supplied to the engine when detected engine speed is greater than a predetermined speed, thereby improving the performance immediately after acceleration is started.

Abstract: An outboard motor includes a transmission mechanism mounted between an output shaft of an engine and a propeller drive shaft. The transmission mechanism includes a clutch. An oil pump for generating a hydraulic pressure so as to switch the clutch is disposed underneath a lowermost one of transmission gears closely thereto. An oil pan is disposed underneath the oil pump and is placed inside an exhaust channel of a gear case.

Abstract: A dog clutch mechanism incorporated in an outboard motor includes a sliding clutch dog member splined to a propeller shaft and having recesses on each end face thereof, and a row of gear teeth formed on an end face of each of a pair of driven gears rotatably mounted on the propeller shaft. Each of the recesses has a bottom surface stepped to provide a corner edge at a stepped portion thereof. Each of the gear teeth has a beveled surface formed at a rear edge as viewed from a rotating direction of the driven gear. When the gear teeth are in mesh with the recesses of the clutch dog member, the corner edge of the stepped bottom surface of each recess is in contact with the beveled surface of the mating gear tooth.

Abstract: A clutch detent mechanism for an outboard motor includes a ball movable with a clutch dog member, a ball retainer member provided in a propeller shaft for retaining the ball in a predetermined position, and a compression coil spring acting on the ball to resiliently force the ball against the ball retainer member. The ball retainer member has a recessed portion for receiving therein the ball to thereby retain the clutch dog member in a neutral position, a front tapered portion provided on one side of the recessed portion for retaining the ball in a position to keep the clutch dog member in a forward shift position, and a rear tapered portion provided on the other side of the recessed portion for retaining the ball in a position to keep the clutch dog member in a reverse shift position.