If the surface is corroded or if the blades are damaged, replace the impeller

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyStarter Clutch Installation
Replace the O-ring [A] with a new one and apply grease.
Apply molybdenum disulfide grease to the starter clutch
shaft [B].
Install:
Starter Clutch [C]
Spacer (Small Diameter) [D]
Spacer (Large Diameter) [E]
Starter Clutch Shaft
Starter Clutch Shaft Holder [F]
Turn the O-ring si ...
Rear Wheel Removal
Raise the rear wheel off the ground with the stand [A].
Remove:
Cotter Pin [A]
Rear Axle Nut [B]
Washer [C]
Rear Axle [D] (from Right Side)
Remove the rear wheel rotation sensor from the caliper
bracket (see Rear Wheel Rotation Sensor Removal in the
Brakes chapter).
...
Battery Installation
Place the battery in the battery case.
Connect the (+) cable to the (+) terminal,
and then connect the (–) cable
to the (–) terminal.
NOTICE
Installing the (–) cable to the (+)
terminal of the battery or the (+)
cable to the (–) terminal of the
battery can seriously damaged
...