Mercury MerCruiser 5.7 Horizon, User Manual

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Section 6 - Storage
Page 88 90-899883173 DECEMBER 2007
Draining the Seawater System
!
CAUTION
Water can enter the bilge when the drain system is open, damaging the engine or causing
the boat to sink. Remove the boat from the water or close the seacock, disconnect and
plug the seawater inlet hose, and ensure the bilge pump is operational before draining.
Do not operate the engine with the drain system open.
IMPORTANT: Only drain the seawater section of the closed‑cooling system.
IMPORTANT: The boat must be as level as possible to ensure complete draining of the
cooling system.
Your power package is equipped with a drain system. Refer to
Drain System
Identification
to determine which instructions apply to your power package.
IMPORTANT: The engine must not be operating at any point during the draining procedure.
IMPORTANT: Mercury MerCruiser requires that propylene glycol antifreeze, mixed to the
manufacturer's instructions, be used in the seawater section of the cooling system for
freezing temperatures or extended storage. Make sure that the propylene glycol antifreeze
contains a rust inhibitor and is recommended for use in marine engines. Be certain to follow
the propylene glycol manufacturer's recommendations.
Drain System Identification
NOTE: All drain plugs are fitted with blue wing nuts.
AIR ACTUATED SINGLE POINT DRAIN SYSTEM
33144
a
b
c
d
a
d
c
33150
Closed‑cooled models Seawater-cooled models
a - Blue drain plug location
b - Blue air pump
c - Air manifold
d - Green indicators