Mercury MerCruiser Product Applications Manual page 103

Cooling System
Openings in seawater pickup should be approximately 3 mm (1/8 in.) maximum to prevent
larger debris from entering and clogging the cooling system.
IMPORTANT: Use a seawater strainer if the seawater pickup openings exceed
3 mm (1/8 in.).
Provisions should be made to minimize galvanic corrosion, given the hull material being
used and the composition of the surrounding components. Some industry standards and
regulations also require that the pickup be connected into the boat's bonding system to
minimize stray current corrosion. Refer to applicable standards and regulations for more
details.
IMPORTANT: External seawater pickup must have an integral seacock.
Page 7A-6
Typical seacock
a
c
g
Typical transom pickup
a - Hose fitting
b - Nut (4)
c - Gasket
d - O-ring (4)
e - Washer (4)
7532
b
d
e
f
h
i
j
7558
f - Screw (4)
g - Plastic plug
h - Pickup
i - Screen
j - Screw (2)
90-863758060 AUGUST 2006