Patent ID: 8196554

Claim:
A sacrificial electrode mounting structure for mounting a sacrificial electrode in a cooling water passageway provided in a cylinder block of a water-cooled engine of an outboard engine unit, comprising: a mounting port provided adjacent to the cooling water passageway and having a mounting hole that opens outwardly from the cooling water passageway for mounting the sacrificial electrode in the cooling water passageway; and a lid member closing an outer end of the hole remote from the cooling water passageway, the lid member having a head portion formed at an outer end thereof and an externally threaded portion, the lid member having the sacrificial electrode fixedly fastened thereto being inserted in the hole and attached to the mounting port with the externally threaded portion engaging with an internally threaded portion formed in the hole of the mounting port with a sealing member sandwiched therebetween, wherein, with the lid member fixedly attached to the mounting port, a space is defined between an outer end portion of the mounting port located outwardly of the internally threaded portion and an outer end portion of the lid member between the externally threaded portion and the head portion, so that part of the sealing member protruding from between the externally threaded portion and the internally threaded portion engaging with each other is received in the space.