Operating instructions
COOLING
SYSTEM
THERMOSTAT
A thermostat controls
the
coolant temperature
as
the
coolant
continuously flows through the closed cooling circuit. When
the
engine is first started
the
closed thermostat prevents
coolant from flowing (some coolant
is
by-passed around
the
thermostat
to
prevent
the
exhaust manifold
from
over-
heating).
As
the engine
warms
up,
the
thermostat gradually
opens.
The thermostat is accessible and can
be
checked,
cleaned, or replaced
easily.
Carry a spare thermostat and
gasket.
If
you
suspect a faulty thermostat, place
it
in
a pan
of
water and
bring
to
a
boiL
A working thermostat should open about
112"
MANIFOLD
PRESSURE
CAP
CHANGING
THE
THERMOSTAT
GASKET
APPLY
SEALANT
TO
GASKET
WHEN-----?1
INSTALLING
THERMOSTAT
Cool
raw
water
flows
through the inner tubes of
the
heat
exchanger.
As
the
engine coolant passes around these
tubes
the
heat of the internal engine
is
conducted
to
the
raw
water
which
is
then pumped
into
the
exhaust system
and
discharged.
The
engine coolant
(now
cooled) flows back though
the
engine
and
the circuit repeats itself.
The engine coolant
and
raw
water are independent of each
other;
this
keeps the engine's water passages clean
from
the
harmful deposits
found
in
raw
water.
Heal
Exchanger
Service
After approximately 1000 hours of operation, remove, clean
and
pressure test the engine's heat
exchanger.
(A
local automo-
tive radiator shop should be able
to
clean
and
test
the
heat
exchanger).
WARNING:
DO
ALl:.OW
WATER
TO
INTO
THE
GENERATOR
HOUSING
...
COVER
THE
AIR
FAN
INLET
WITH
FOIL
WHEN
REMOVING
THE
END
CAP
-
GASKET
O-RING
NOTE:
Operating
in
silty and/or tropical waters
requlre
that a heat exchanger cleaning be peifonned
more
often then
every 1000 hours.
ZINC
ANODE
A
zinc
anode
(or pencil)
is
located
in
the
raw
water cooling
circuit within
the
heat exchanger. The purpose of the
zinc
anode is
to
sacrifice itself
to
electrolysis action taking place
in
the
raw
water
cooling circuit, thereby reducing
the
effects
of electrolysis on other components of
the
system. The
con-
dition
of
the
zinc anode should be checked monthly
and
the
anode cleaned or replaced,
as
required. Spare anodes should
be carried onboard.
NOTE:
Electrolysis
is
the result
of
each particular installation
and vessel location, not that
of
the
engine.
If
the
zinc
anodes need replacement,
hold
the
hex
boss into
which
the
zinc
anode is'threaded
with
a wrench while
loosening
the
anode with another wrench. This
prevent~
the
hex boss
from
possibly tearing off the exchanger
shell.
After
removing
the
zinc,
note
the
condition
of
it.
If
the
zinc
is
in
poor condition, there are probably alot of
zinc
flakes within
the
exchanger.
Remove
the
end of
the
heat exchanger
and
clean
the
inside of all
zinc
debris. Always have a spare heat
exchanger end gasket
in case the present one becomes
damaged
when
removing the end
cover.
Replace
the
gasket
(refer
to
your engine model's heat exchanger end gasket part
number),
O-ring
and
cover, and install a
new
zinc
anode.
NOTE:
The
threads
of
the zinc anodes
are
pipe threads
and
do
not
require
sealant. Sealant should not
be
used as it may
insulate
the
zinc from the metal
of
the
heat exchanger
housing preventing electrolysis action
on
the
zinc.
ZINC
ANODES
NEW
THROW
OUT
THROW
OUT
CLEAN
AND
REUSE
Engines & Generators
14