Flushing Seawater Cooling System; Engines With Stern Drive Seawater; Pickup Pump; Check/Clean Seawater Strainer - Mercury 305 CID Service Manual

Flushing Seawater Cooling
System
If engine is operated in salty, polluted or mineral-
laden waters, seawater cooling system should be
flushed periodically (preferably after each use) with
fresh water to reduce corrosion and prevent the
accumulation of deposits in the system. Seawater
cooling system also should be thoroughly flushed
prior to storage.
! WARNING
When flushing, be certain the area around pro-
peller is clear, and no one is standing nearby. To
avoid possible injury, remove propeller.
! CAUTION
Do not run engine above 1500 RPM when flush-
ing. Suction created by seawater pickup pump
may collapse flushing hose, causing engine to
overheat.
IMPORTANT: If cooling system is to be flushed
with boat in the water, seacock (if so equipped)
must be closed, or water inlet hose must be dis-
connected and plugged to prevent water from
flowing into boat.
! CAUTION
Watch temperature gauge at dash to ensure the
engine does not overheat.

Engines with Stern Drive Seawater

Pickup Pump

! CAUTION
To prevent engine or stern drive unit damage DO
NOT run engine or drive unit without water being
supplied to water intake openings on gear hous-
ing.
If flushing cooling system with boat in water, raise
drive unit to trailer position, install flushing attach-
ment and lower drive unit to full IN/DOWN position.
1. Install Quicksilver Flushing Attachment (or
equivalent) over water intake openings in gear
housing.
Index
6A-8 - SEAWATER COOLING MODELS
2. Connect hose between flushing attachment and
water tap.
a - Quicksilver Flushing Attachment
b - Garden Hose
3. With drive unit in normal operating position, par-
tially open water tap (about 1/2 maximum) and al-
low cooling system to fill completely. Cooling sys-
tem is full when water is discharged through the
propeller. Do not use full tap water pressure.
4. Place remote control in NEUTRAL, idle speed
position and start engine. Operate engine at idle
speed, in NEUTRAL, for about 10 minutes, or un-
til discharge water is clear. Watch temperature
gauge on instrument panel to ensure that engine
does not overheat.
5. Stop engine. Shut off tap water and remove flush-
ing attachment.

Check/Clean Seawater Strainer

NOTICE
Refer to manufacturer's instructions for in-
formation on checking and cleaning of oth-
er than Quicksilver Seawater Strainer.
1. Visually inspect seawater strainer through glass
top.
! WARNING
When cleaning seawater strainer, close seacock,
if so equipped. If boat is not equipped with a sea-
cock, remove and plug seawater inlet hose to
prevent a siphoning action that may occur, allow-
ing seawater to flow from the drain holes or re-
moved hoses.
a
b
72672
90-823225--1 1096