Mercury 200 OptiMax Manual page 110

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
(–)
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.
Water Pressure and Speedometer Hose or Tubing
NOTE: This applies to models without SmartCraft gauges.
OUTBOARD INSTALLATION
a
c
(-)
a
b
(-)
c - Ground cable
d - Cranking battery
102
d
d
15497