Patent attributes
A boat propulsion system that easily and finely adjusts the rotational speed of a propeller includes an outboard motor including an engine, a propeller, a shift mechanism, and a control device. The control device controls engaging states of clutches so that the rotational speed of a second power transmission shaft is substantially the same as the rotational speed of a third power transmission shaft in a first mode in which the shift position is a forward or a reverse position. The control device controls the engaging states of the clutches so that the rotational speed of the third power transmission shaft is lower than the rotational speed of the second power transmission shaft in a second mode in which the shift position is the forward or the reverse position.
