Yamaha T8 Rigging Manual page 140

Outboard Rigging Guide - 2001
Twin Engine
BATTERY SWITCH SELECTION
MODE
SYSTEM OFF
NORMAL OPERATION
BACK-UP CRANKING
NOTE:
1. SWITCH POSITION "BOTH" SHOULD NOT BE USED FOR BACK-UP CRANKING. If Battery
1 is discharged and the "BOTH" position is selected, then Battery 2 will discharge into Battery 1.
2. Switch #3 is not required, the battery isolator on the motor will prevent current from flowing to the
electrical components on the engine, even if the small wire remains connected to the battery.
However, the Switch #4 can be installed to shut off electrical power to the accessories.
Optional: Isolator lead 3 from both engines could be hooked to the accessory battery.
3
SWITCH #1 POSITION
OFF
BATTERY 1
BATTERY 2
3-29
SWITCH #2 POSITION
OFF
BATTERY 2
BATTERY 1
Battery Installations