| 摘要 |
PROBLEM TO BE SOLVED: To provide the idling exhaust structure of an outboard motor capable of suppressing an exhausting noise and the temperature at low levels, respectively at idling operation. SOLUTION: This idling exhaust structure of the outboard motor is composed by housing a four-cycle engine in the cowling of a housing comprising an upper case 6 and a lower case 7 together with the cowling, housing an oil pan 9 and a muffler 11 connected to the lower part thereof in the upper case 6, passing an exhaust pipe 15 through a hollow part 9a which is installed into the oil pan 9 in a vertical direction, and then opening the end of the pipe 15 toward the muffler 11. At idling operation, an exhaust gas discharged into the muffler 11 from the engine through the exhaust pipe 15 is discharged in the upper area of water wall in the upper case through the oil pan 9 and is further discharged in the atmosphere through an idling expansion chamber S formed in the upper part of the upper case 6. |
