Outboard motor and boat

An outboard motor comprising:

• an engine;
• a propeller shaft;
• a propeller attached to the propeller shaft;
• a transmission to transmit rotation of the engine to the propeller shaft;
• an upper accommodation body that accommodates at least a portion of the engine;
• a lower accommodation body that accommodates at least a portion of the propeller shaft;
• and
• a steering to cause the lower accommodation body to rotate about a steering axis with respect to the upper accommodation body;
• wherein
• the upper accommodation body includes an upper exhaust channel including an upper exhaust port that communicates with the engine;
• the lower accommodation body includes a lower exhaust channel including a lower exhaust port;
• and
• the upper exhaust channel and the lower exhaust channel are switchable between a communication state where the upper exhaust channel and the lower exhaust channel communicate with each other, and a non-communication state where the upper exhaust channel and the lower exhaust channel do not communicate with each other based on at least one of a rudder angle of the steering and a speed of the engine.