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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblySwitch Inspection
Using a hand tester, check to see that only the connections
shown in the table have continuity.
Special Tool - Hand Tester: 57001-1394
For the switch housings and the ignition switch, refer to
the tables in the Wiring Diagram.
If the switch has an open or short, repair it or replace it
w ...
Piston Ring Thickness Inspection
Measure the piston ring thickness.
Use the micrometer to measure at several points around
the ring.
Piston Ring Thickness
Standard:
Top [A] 0.77 0.79 mm (0.0303
0.0311 in.)
Second [B] 0.78 0.79 mm
(0.0307 0.0311 in.)
Service Limit:
Top 0.70 mm (0.0276 in.)
Second 0.71 mm (0.0280 ...
Race Mode Display
This mode gives priority to reading
the gear position rather than the
speedometer reading.
The gear position indicator can
be displayed at the position of the
speedometer on the normal mode.
Also the speedometer is displayed instead
of the clock on the normal mode.
This mode can be used ...