Patent ID: 9174716
Filing Date: 2015-11-03
Classification: B63H

Abstract:
1. A lower unit of an exhaust structure for an outboard motor to discharge exhaust gas from an engine into water, comprising: a gear case comprising: a propeller shaft disposed from the gear case; a bearing housing supporting the propeller shaft and in communication with an exhaust passage; a propeller coupled to the propeller shaft; and a propeller boss provided to the propeller and coupled to the propeller shaft, comprising: wherein the propeller is provided at an outside of the propeller boss, wherein the outside diameter of the front end portion is larger than the outer diameter of the rear end portion of the gear case, and wherein the exhaust gas passes through the bearing housing from the exhaust passage, and passes through the hollow structure and inside of the propeller boss and is discharged out the opening of the rear end portion of the propeller boss.