Mercury 250 XS OptiMax Operation, Maintenance & Installation Manual page 115

OUTBOARD INSTALLATION
BATTERY CABLE CONNECTIONS
Single Outboard
b
Dual Outboards
Connect a common ground cable (wire size same as engine battery cables)
between negative (–) terminals on starting batteries.
b
c
a - Red sleeve ‑ positive (+)
b - Black sleeve ‑ negative (–)
c - Ground cable
d - Cranking battery
eng
a
(-) (-)
b
a
(-)
a -
b -
(+) (+)
c -
c
15496
a
(-)
d
105
Red sleeve ‑ positive
(+)
Black sleeve ‑
negative (–)
Cranking battery
d
15497