Cooling system
59
The water circulating in the seawater system is cool-
ing the reverse gear oil, the engine inlet air, the fresh-
water and the engine oil. In an installation with a wet
exhaust system this water is also used to cool the ex-
haust gases. The engines should in most cases be
equipped with a seawater filter
The Volvo Penta cooling system is designed for sea-
water temperatures of max. 32°C (90°F).
Sea-water intake
The sea-water intake should preferably be made of
bronze alloy (brass is unsuitable since it corrodes due
to its high zinc content). In the case of boats made of
steel, however, the same material as that in the boat
hull must be used. If the hull and sea-water intake ma-
terials differ, then it may be necessary to insulate the
intake electrically from the hull to avoid galvanic cor-
rosion.
The sea-water intake, the sea-cock and the strainer
must have a sufficiently large through-flow area to
avoid constriction losses and the subsequent reduced
water supply to the pump. The depressure at the inlet
of the sea-water pump must not exceed 30 kPa (4.35
psi).
The hose connection on the engine has a diameter of
32 mm (1¼"). The sea-water intake should have a
hose with an internal diameter of 32 mm (1¼").
Minimum flow area of the strainer = 1.5 x hose inner
cross section area.
The sea-water intake must be located so far below the
waterline that the strainer is under water even when
the boat heels over or moves in heavy seas. Do not
locate the sea-water intake too far forward in the boat.
Seawater system
Fit the bottom strainer (1) with opening (strainer) fac-
ing forwards (A) except on sailing boats where the
opening (strainer) should face astern (B) to prevent
water from beeing forced up into the coolant line when
sailing. When a motor boat is being towed, the sea
cock must be closed.
Coat the sealing surfaces with a suitable compound,
such as silicon rubber. Secure the bottom strainer
with the nut (2).
Fit the sea-water shut off valve and hose connection
(3). Use sealing compound of a non-hardening type.
NOTE! Always use two hose clamps on each hose
connection in the sea-water system. Position hose
calmp screws (4) as per figure.
A
B
1. Strainer
2. Bottom cock
3. Seawater filter
4. Anti siphoning valve
5. Seawater pump
2
3
4
5
1
2
3
4
1
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