| 摘要 |
PURPOSE:To prevent the occurrence of abnormal noise at an auxiliary exhaust port part and damage to an exterior view, by making the cold injection water fed by a pump flow down to a main exhaust passage alone, in case of an outboard motor. CONSTITUTION:A lower casing 22 is connected to a lower part of an upper casing 21, forming a propeller casing 20, and an exhaust guide 23 is connected to an upper part of this casing 20. A vertical main exhaust passage 24 is formed in this propeller casing 20, and the lower part is opened to the underwater via a main exhaust port. An exhaust pipe 25 is installed in a shaft center part inside the main exhaust passage 24, and a lower end 25b of the exhaust pipe 25 is made to extend as far as the vicinity of the upper casing 21 and opened downward. An upper part 14a of the passage 24 is interconnected to a primary auxiliary expansion chamber 26, a secondary auxiliary expansion chamber 27 and a tertiary auxiliary expansion chamber 31 in consecutive order. At the time of idling, exhaust is discharged to the outside from an auxiliary exhaust port 32 by way of these auxiliary expansion chambers 26, 27 and 31. |
