Flushing Cooling System - Mercury 350 Mag MPI Manual

CC518
CC921

Flushing Cooling System

When flushing, be certain the area around propeller is clear, and no one is standing nearby. To avoid
possible injury, remove propeller.
Do not run engine above 1500 rpm when flushing. Suction created by seawater pickup pump may col-
lapse flushing hose, causing engine to overheat.
Watch temperature gauge on dash to ensure that engine does not overheat.
If cooling system is to be flushed with boat in the water, water inlet valve (if so equipped) must be
closed, or water inlet hose must be disconnected and plugged to prevent water from flowing into boat.
If boat is in the water, do not open water inlet valve until engine is to be restarted, to prevent contami-
nated water from flowing back into engine.
NOTE: To prevent silt and/or salt buildup in cooling system, flush with freshwater at specified intervals.
1
If boat is equipped with a circulating pump hose flush device, attach water hose to flush device on circu-
lating pump hose.
2
If boat is not equipped with a circulating pump hose flush device, disconnect water inlet hose (lower hose)
from aft end of seawater pickup pump. Using appropriate connector, connect hose between connector and water
tap.
3
Partially open water tap (about 1/2 maximum).
4
Place remote control in NEUTRAL, idle speed position, and start engine. Operate engine at idle speed, in
NEUTRAL, for about 10 minutes or until discharge water is clear.
5
Stop engine. Shut off water, remove flushing connector from pump inlet and reconnect water inlet hose. Tight-
en hose clamp securely.
6
Attach water hose to flush device on circulating pump hose.
7
Partially open water tap (about 1/2 maximum).
8
Do NOT start engine. Allow water to run for approximately 5 minutes. Shut off water and remove water hose
from flush device.
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