Cooling system for outboard motor
A cooling system includes a coolant distributing device arranged to distribute coolant discharged from a water pump to both an engine and a transmission device. The coolant distributing device includes a coolant relay section, an inlet conduit member, an outlet conduit member, and a transmission cooling conduit member, and supplies a portion of the coolant discharged from the water pump to a highest portion of a water jacket of the transmission device, and discharges the water from a lowest portion of the water jacket. The cooling system effectively cools the transmission device with a simple construction facilitating assembly and maintenance.
1. A cooling system for an outboard motor including an engine installed in an upper portion of a casing, a transmission device installed inside the casing, and a water pump arranged to pump coolant for cooling the engine, the cooling system comprising:
a coolant distributing device arranged to distribute coolant discharged from the water pump; wherein the coolant distributing device includes:
a coolant relay section arranged to distribute the coolant to both the engine and the transmission device; and
a transmission cooling conduit member branched from the coolant relay section to supply a portion of the coolant to the transmission device.
2. The cooling system for the outboard motor according to claim 1 , wherein the coolant distributing device is arranged to supply the portion of the coolant discharged from the water pump to a highest portion of a water jacket of the transmission device and discharge the coolant from a lowest portion of the water jacket.
3. The cooling system for the outboard motor according to claim 1 , wherein the water pump is arranged such that at least a coolant inlet and a coolant outlet thereof face an outside of the casing, and the coolant distributing device includes:
the coolant relay section located outside the casing and in communication with an engine coolant supply path in the casing;
an inlet conduit member located outside the casing and having an upstream end connected to a water intake provided below the casing and a downstream end connected to the coolant inlet;
an outlet conduit member located outside the casing and arranged to connect the coolant outlet and the coolant relay section; and
the transmission cooling conduit member having a first end connected to the coolant relay section and a second end connected to a highest portion of a cooling portion of the transmission device.
4. The cooling system for the outboard motor according to claim 3 , wherein bore diameters of the inlet conduit member and the outlet conduit member are different from a bore diameter of the coolant relay section.
5. The cooling system for the outboard motor according to claim 3 , wherein at least one of the inlet conduit member, the outlet conduit member, and the transmission cooling conduit member includes a flexible hose member.