Mercury 225 Manual page 134

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
HOSE AND TUBING CONNECTIONS
Fuel Hose
The minimum fuel line inside diameter (I.D.) is 8 mm (5/16 in.),
with a separate fuel line/fuel tank pickup for each engine.
Fasten the remote fuel hose to the fitting with a hose clamp.
Oil Hoses
Connect the remote oil hoses to the engine hose connections.
Fasten hose connections with cable ties.
OUTBOARD INSTALLATION
b
a
(-)
a
(-)
d
122
d
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