Mercury MerCruiser MCM 454 Mag MPI Service Manual page 67

MAINTENANCE
9. Insert a small wire (repeatedly) to make sure that speedometer pitot tube, anode cavity
vent hole, and anode cavity drain passage are unobstructed and drained.
Typical Bravo Drive Unit
10. Crank engine over slightly with starter motor to purge any water trapped in seawater
pickup pump. DO NOT ALLOW ENGINE TO START.
11. After cooling system has been drained completely, coat threads of drain plugs with
Quicksilver Perfect Seal. Install all drain plugs and tighten securely. Reconnect all hoses
and tighten all hose clamps securely.
IMPORTANT: MerCruiser recommends that propylene glycol antifreeze (nontoxic
and biodegradable, which makes it friendly to lakes and rivers) be used in sea-water
section of the cooling system for cold weather 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 recom-
mendations.
12. For additional assurance against freezing and rust, remove the thermostat cover and
thermostat. Fill the engine seawater cooling system with a mixture of antifreeze and tap
water mixed to manufacturer's recommendation to protect engine to the lowest temper-
ature to which it will be exposed during cold weather or extended storage. Using a new
gasket, reinstall thermostat and cover. Tighten cover bolts to 30 lb-ft (41 Nm).
NOTE: Hoses shown removed for visual clarity. Do not remove hoses.
Index Index
Page 1B-50
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a - Speedometer Pitot Tube
b - Anode Cavity Vent Hole
c - Anode Cavity Drain Passage
a - Housing
b - Gasket
c - Thermostat
d - Spacer
e - Fill Here
b
c
a
a
b
c
d
e
SERVICE MANUAL NUMBER 23
71217
90-861326--1 MARCH 1999