Specifications
COOLING
SYSTEM
THERMOSTAT
A thennostat controls
the
coolant temperature
as
the
coolant
continuously
flows
through the closed cooling
circuit.
When
the
engine
is
first
started
the
closed thennostat
prevents
coolant
from
flowing
(some
coolant
is
by-passed
through
the
thennostat
to
p~vent
the
exhaust manifold
from
overheating).
As
the
engIne
wanns
up,
the
thennostat gradually
opens.
The
thennostat
is
accessible
and
can
be
checked,
cleaned,
or
replaced
easily.
Carry a
spare
thennostat
and
gasket.
GASKET
(APPLY
SEALANT
TO
BOTH
SIDES)
THERMOSTAT
TEST
If
you
suspect a
faulty
thennostat, place it
in
a
pan
of water and
bring
to
a
boil.
A
working
thennostat should
open
about
112"
ZINC
ANODE
~
zi~c
~o~e
(or pencil)
is
located
in
the
raw
water cooling
CIrcUlt
wIthm
the heat
exchanger.
The purpose of
the
zinc
~ode
is
to
sacrifice itself
to
electrolysis
action
taking
place
1ll
the
raw
water cooling circuit,
thereby
reducing
the
effects
of
electrolysis
on
other components of
the
system.
The
condition
of
the
zinc
anode
should
be
checked monthly
and
the
anode
cleaned or replaced
as
required.
Spare
anodes
should
be
carried
on
board.
NEW
REPLACE
CLEAN
&
REUSE
NOTE:
Electrolysis is
the
result
of
each
particular installation
and vessel
location,
not that
of
the
generator.
If
the
zinc
anode
needs replacement, hold
the
hex
boss
into
which
the
zinc
anode
is
threaded
with
a
wrench
while
loosening
the
anode
with
another
wrench.
This
prevents
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 a lot 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
sealing
gasket (refer
to
your engine model's heat exchanger
end
gasket part
number),
O-ring,
cover,
and
install
a
new
zinc
anode.
NOTE:
The
threads
of
the
zinc
anodes
are
pipe
threads
and do
not
require
sealant.
sealant shmdd not
be
used
as
it
may
insulate
the
zinc
from the metal
of
the
heat exchanger
housing preventing electrolysis
action
on
the
zinc.
ZINC
ANODE
HEAT
EXCHANGER
"
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
through
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.
Heat
Exchanger
Service
After
approximately
1000
hours
of operation,
remove,
clean
and
pressure test
the
engine's heat
exchanger.
(A
local
automotive radiator shop should be
able
to
clean
and
test
the
heat
exchanger.)
NOTE:
Operating
in
silty and/or tropical waters may
require
that a heat exchanger cleaning
be
perfonned
more
often
than
every 1000
hours.
Engines & Generators
13