Installation manual
COOLING
SYSTEM
HEAT
EXCHANGER
The heat exchanger
is
a copper cylinder which encloses a
large number
of
small copper tubes. Raw water
is
pumped
through the small copper tubes and the fresh water coolant
from
the engine
is
circulated around the copper tubes. The
raw water removes heat from the fresh water coolant.
Heat
Exchanger
Service
After approximately 1000 hours
of
operation, remove, clean
and pressure test the engine's heat exchanger. (A local auto-
motive 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.
Zinc
Anode
A zinc anode, or pencil,
is
located
in
the raw water cooling
circuit within the heat exchanger. The purpose
of
having
zinc anodes
is
to sacrifice them to electrolysis action taking
place
in
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.
NOTE:
Electrolysis action is the result
of
each particular
installation and vessel location; not that
of
the engine.
CLEAN
OUT
BOTH
ENDS
ZINC
ANODE
ALSO
SERVES
AS
A
DRAIN
FOR
THE
RAW
WATER
SYSTEM
HEAT
EXCHANGER
TO
REMOVE
HEAT
EXCHANGER
17
ZINC
ANODES
NEW
REPLACE
CLEAN
&
REUSE
If the zinc anodes need replacement, hold the hex boss into
which the zinc anode
is
threaded with a wrench while loos-
ening 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 dam-
aged when removing the end cover. Replace the gasket (refer
to
your engine model's heat exchanger end gasket part num-
ber),
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 hou;-
ing preventing electrolysis action on the zinc.
CLEAN
OUT
ACCUMULATED
DEBRIS
GASKET