Mercury 305 CID, Service Manual, Page: 815 / 967

CLOSED COOLING MODELS - 6B-41 90-823225--1 1096
Cold Weather or Extended
Storage
! CAUTION
Seawater section of cooling system MUST BE
COMPLETELY drained for winter storage, or im-
mediately after cold weather use, if the possibil-
ity of freezing temperatures exist or if the boat is
to be stored for an extended period. Failure to
comply may result in trapped water causing
freeze and/or corrosion damage to engine.
Seawater Section Draining
Instructions
IMPORTANT: Observe the following information
to ensure complete draining of cooling system.
•
Engine must be as level as possible.
•
A wire should be repeatedly inserted into all
drain holes to ensure there are no obstruc-
tions in passages.
•
It may be necessary to lift, lower or bend dis-
connected hoses to allow water to drain com-
pletely.
! CAUTION
If seawater section of the Closed Cooling System
is to be drained with boat in the water, seacock
(water inlet valve), if boat is so equipped, must be
closed or water inlet hose MUST BE discon-
nected from seawater pickup pump and plugged,
to prevent water from flowing into cooling sys-
tem and/or boat.
IMPORTANT: If a seacock (water inlet valve) is to
be installed for draining purpose, valve used
MUST have an internal cross-sectional area
equal or greater than water inlet hose to prevent
restricting water flow during normal operation. A
1-1/4 in. (32mm) or larger brass ball valve or gate
valve is recommended.
1. Remove drain plug from port and starboard ex-
haust manifolds.
74073
a
Starboard Side (Port Side Similar)
a - Drain Plug
2. Disconnect heat exchanger-to-starboard ex-
haust manifold hose at manifold. Lower hose and
allow to drain.
75212
b
a
Typical Starboard Hose Shown
a - Starboard Exhaust Manifold
b - Starboard Hose