Several embodiments of venting arrangements for the lubricant pump of a two-cycle, crankcase compression internal combustion engine for an outboard motor and having a positive lubricating system. In each embodiment, the lubricant pump is provided with a vent passage that extends from an upper portion of a chamber of the pump for venting air from it. In each embodiment, an arrangement is provided for permitting air flow from the fluid pump without returning to the fluid pump. In some embodiments, this means comprises a check valve and in another embodiment, it comprises a restricted orifice.