Mercury 300 XS OptiMax Manual page 129

BATTERY CABLE CONNECTIONS
Single Outboard
Dual Outboards
Connect a common ground cable (wire size same as engine battery cables)
between negative (–) terminals on starting batteries.
b
a - Red sleeve ‑ positive (+)
b - Black sleeve ‑ negative (–)
c - Ground cable
d - Cranking battery
eng
OUTBOARD INSTALLATION
a
b
(-) (-)
a
c
(-)
(+) (+)
c
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a
b
(-)
123
a - Red sleeve ‑ positive
(+)
b - Black sleeve ‑
negative (–)
c - Cranking battery
d
d
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