A throttle body adapter connects a throttle body and an air intake manifold spaced from the throttle body in a marine engine. The throttle body adapter has an air passage having an inlet and an outlet of different shapes. The throttle body adapter has threaded openings which allow a fuse box, an electronic control module, a hose fitting and a mounting bracket for a beauty cover to be mounted to the throttle body adapter with threaded fasteners. The throttle body adapter further comprises a threaded opening adapted to receive an air inlet temperature sensor.