An outboard engine unit capable of efficiently cooling the interior of an engine cover is disclosed. The outboard engine unit includes a cooling opening capable of guiding air to an interior from an upper part of the engine cover, a first intake channel having a first outlet open to an upper front end and communicating with the opening, a partition wall disposed so as to be oriented substantially in a perpendicular direction below the first outlet; and a second intake channel extending substantially in the perpendicular direction along a rear wall of the engine cover rearward of the partition wall. The outboard engine unit is configured so that air directed from the cooling opening to the interior of the engine cover is directed to the throttle unit via the second cooling air intake channel.