Gearboxes, underwater parts and spare parts for Yamaha outboards
The underwater part (lower unit or gearcase) is located in the lower section of an outboard motor. It contains the gearbox and other components that transmit the rotary motion of the engine to the propeller.
In the gearbox, the speed of the motor is adjusted via gear wheels. At the same time, the torque is increased so that the propeller can drive the boat efficiently. In addition, the gearbox enables the change between forward gear, neutral position and reverse gear.
Typical spare parts in the underwater section
The underwater part of a Yamaha outboard motor contains several important components:
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Gearcase
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propeller shaft
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Drive shaft
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Gears for forward and reverse gears
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Bearings and shaft seals
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Water pump with impeller
These components work together to reliably transfer the engine power to the propeller.
Water pump in the underwater section
The engine's water pump is also located in the underwater section. It draws in water from the environment and feeds it through the engine's cooling system. The impeller of the water pump is driven by the drive shaft.
Selecting the right gearbox spare parts
The selection of gearbox and underwater spare parts is based on several technical specifications:
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Yamaha engine series
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Engine power (hp)
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Year of manufacture
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Shaft length of the engine
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Yamaha part number
This information ensures that the spare parts fit the respective transmission type and engine generation.
