| 摘要 |
PURPOSE:To keep off noises including a shell sound or the like leaking from an idle passage by leading at least a part of exhausts in a main passage into a silencer installed in a cowling covering an engine, while exhausting it out of an aerial exhaust port. CONSTITUTION:An engine is covered by cowlings 12, 14, while its lower part is connected to an exhaust guide 16 and casings 18, 20, constituting an outboard motor as a whole. Exhaust discharged out of the engine 10 is led into main exhaust passages 30, 32. At this time, the exhaust discharged out of the main exhaust passage 32 is led into two expansion chambers 34, 36 in order, while it is led into an expansion box 60 via an interconnecting passage 56 and a tube 58. The exhaust expanded inside the expansion box 60 and dropped in temperature is led into another expansion chamber 72 via a tube 70 and then further led into another expansion chamber 76 via a through passage 74. Finally the exhaust is discharged into the air via an idle passage 78 and an aerial exhaust port 80. |
