6
Engine Cooling
COOLING SYSTEM OVERVIEW
Refer to Figure 1. The engine is cooled by a pres-
surized, closed-loop liquid cooling system. Coolant
is pumped through passages in the engine block,
head and exhaust manifold. The exhaust manifold
also serves as the engine coolant reservoir.
The heat exchanger is mounted inside the exhaust
manifold. Raw water (the flotation water) is pumped
through tubes in the heat exchanger to cool the en-
gine coolant and then is passed through a hose into
the exhaust-water mixer to cool the exhaust gases.
The raw water is expelled from the boat along with
the exhaust gases. The V-belt drives the coolant
and the raw water pumps.
RAW
WATER IN
EXHAUST &
RAW WATER
OUT
THERMOSTAT
HOUSING
BLOCK
DRAIN CAP
RAW WATER
PUMP PULLEY
COOLANT
RAW WATER
EXHAUST-WATER
MIXER WITH HIGH
TEMPERATURE
EXHAUST SWITCH
RAW WATER FLOW
SENSOR
HOSE BARB TO
CONNECT COOLANT
RECOVERY TANK
EXHAUST MANIFOLD &
COOLANT RESERVOIR
PRESSURE CAP &
COOLANT FILL NECK
COOLANT
PUMP PULLEY
INSULATED
GASOLINE
HOSE
WHEN REQUIRED,
REMOVE THIS HOSE
AND CONNECT A
SIPHON BREAK
(PAGE 7)
DISCONNECT THE
RAW WATER PICKUP
HOSE HERE FOR THE
RAW WATER PICKUP
TEST (PAGE 8)
FIGURE 1. ENGINE COOLING SYSTEM
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