Engine Cooling Systems - Four winns 338 Vista Owner's Manual

Under your normal load conditions, the engines
should turn within the maximum RPM range when at
full throttle. If the engines exceed the recom mended
RPM, an increase in pitch or diameter is required.
If the engine RPM is too low, a de crease in pitch or
diameter is required.
The load carried in a boat will directly affect perfor-
mance of the engine. If an engine that is not develop-
ing full power, be sure the engine is properly tuned
and load conditions are those normally experienced,
before changing propellers.
For shipping reasons, the propellers are not factory
installed. Initial installation of the propel lers will be
performed by the dealer during pre-delivery ser vice.
Consult your specific engine manufacturer's owner's
manual for propeller installation instructions. See
Figure E3.
Front Propeller Nut
Propeller Shaft
Figure E3: Duo Prop Installation
NOTICE
Should it be necessary to change propel lers,
always use an appro priate propeller removal
tool or "Prop Puller." DO NOT attempt removal
using a ham mer. Dam age to the propeller or
propeller shaft can result.
Be sure the propellers are of the correct blade con-
figuration, diame ter, pitch, and shaft size to assure
good performance. For additional information on
factors affecting performance and/or assistance with
your selection, please consult your Four Winns dealer.
E - 5

ENGINE COOLING SYSTEMS

A. Raw Water Cooling
Most of the 338 Vista® stern drive engines utilize a
raw water cooling system. This cooling system is a
seawater system. Seawater (raw) water is taken in
through water inlets on the both sides of the lower
Engines, Drives and Instrumentation - Section E
Front Propeller
Rear Propeller
Rear Propeller Nut
gear unit of the stern drives models. Water pumped to
the engine by the seawater pump is circulated through
the engine by the engine circulating pump. A thermo-
stat controls the engine operating temperature by
determining the amount of water to be taken in,
recirculated and discharged. The water is discharged
through an idle exhaust relief and the exhaust through
the propeller hub. A temperature gauge(s) located
on your instrument panel monitors engine(s)
temperatures.
Never operate your engine without a
thermostat. Engine damage can occur and is
considered operator negligence and therefore
not covered under the engine warranty.
If engine should overheat, turn off engine,
look for obstructions to water pick-up. If any
obstructions are found, clear the obstructions
and run engine again at 1500 RPM in neutral
and check temperature gauge to verify
condition. If overheating still occurs, return to
port at low RPM to prevent excessive over-
heating and engine damage. Consult with
your certified engine dealer for service.
NOTICE
When laying up the boat for winter it is
important that the cooling system be flushed
with fresh water so that deposits do not dry
and to prevent the buildup of salt crystals.
Please consult your engine owner's/operator's
manual for proper engine and cooling system
winterization procedures.
B. Fresh Water Cooling - Optional
An available option on certain 338 Vista
engines models is a "closed water cooling" system.
This system provides adequate engine cooling without
exposing the internal engine to the detrimental effects
of surface water, including salt, highly polluted or silt-
laden water. The engine owners manual provides
addi tional infor mation regarding service and mainte-
nance of this equipment. See your Four Winns dealer
for availability.
stern drive
®
Owner's Manual Page 56