Water cooling device for outboard motor

摘要

A water cooling system for an outboard motor can include a casing that is configured to be submerged in water at a lower part thereof and to support an internal combustion engine on an upper part thereof. The system can have an exhaust passage that is formed in the casing and through which exhaust gas from the internal combustion engine is inducted from the upper part of the casing toward the lower part, a portion of the exhaust passage between an upstream-side passage and a downstream-side passage being configured as an expansion chamber. Also provided is a cooling water passage extending along the exhaust passage and a drain port that permits water to be discharged into the downstream-side passage after passing through the cooling water passage.