Patent ID: 8066539

Claim:
A marine propulsion system comprising: an engine; a propeller driven by the engine; a transmission mechanism that operates in at least a lower speed reduction ratio and a higher speed reduction ratio, and transmits a driving force generated by the engine to the propeller with a speed thereof shifted to one of the lower speed reduction ratio and the higher speed reduction ratio; a control lever section operated by a user to control a drive of the engine; and a control portion that controls a shift between the lower speed reduction ratio and the higher speed reduction ratio of the transmission mechanism based on operation of the control lever section by the user; wherein the control portion controls a shift between the lower speed reduction ratio and the higher speed reduction ratio of the transmission mechanism based on a transmission control map which provides a reference for a shift between the lower speed reduction ratio and the higher speed reduction ratio of the transmission mechanism based on an engine speed and a lever opening of the control lever section; and the control portion includes: a first control section provided in the control lever section; a second control section provided in the engine; a first communication line communicating between the first control section and the second control section; and a second communication line provided independently of the first communication line communicating between the first control section and the second control section.