Operator`s manual

Exhaust Back-Pressure
Exhaust back -pressure should be checked prior
to
putting a generator into service. (Refer to
illustration.) Excessive back-pressure will affect
the engine's performance and the generator's
power output.
To measure the engine's back-pressure, either a
mercury manometer or a water column must be
acquired. A boatyard or marine mechanic should
have a clear plastic tube and taping one end to a
yardstick and fitting the other end with a
114 inch
NPT (National
Pipe Tap) fitting. Fill the tube
half-full with water.
If your generator set does not
have a tapped hole in its exhaust manifold, one
must
be drilled and tapped for a 114-inch NPT
fitting.
Measure back -pressure at the exhaust elbow when
the generator is under a full load. Back-pressure,
as measured by a manometer or water column,
should not be over the following specifications:
3 inches
of mercury (0.104 kg/cm
2
)
39 inches of water in the column (.099 kg/cm
2
at 4° C)
22 ounces of psi
1
112 psi
"
\
' "
"
I~
::xhaust
::Ibow
~Exhaust
f\
Mercury
Manometer \
\
NOTE: Other pressure gauges may be available to test for exhaust back-pressure.
Oil Drain
An
oil sump drain hose is installed on the engine with the discharge end secured by a bracket at the front
of the engine. Oil may be drained from this hose by removing the cap and the discharge end of the hose
from the support bracket and lowering the hose into a container. The hose cap fitting is
114 inch-NPT
(National
Pipe Tap) and can he extended, or have a pump added, for easier removal of the old oil, if
desired.
Cooling System
The generator's engine is fresh water cooled
by an engine-mounted heat exchanger. Sea water is used as
the heat exchange's cooling medium. Sea water is pumped into the exchanger by a sea water pump and is
then injected into the exhaust discharge, carrying with it the heat removed from the engine's fresh water
cooling system.
Sea water should be supplied to the sea water pump through a flush-type hull fitting using a wire-
reinforced hose between the thm-hull fitting and the sea water pump. This
sea water should be directed
through a visual-type sea water strainer and then delivered
to the pump. Hoses routed from the thm-hull
fitting
to the strainer and to the sea water pump should be wire-reinforced to prevent the hose from
collapsing during the generator's operation (suction from the pump
may collapse a non-reinforced hose.)
Sea water strainers should he mounted at or below the water line to make sure the sea water line remains
primed.
37
WESTERBEKE GENERATORS