Four winns SL Series Owner's Manual page 77

C. Anti-Syphon Valves
The fuel withdrawal line is equipped with an anti -
syph on valve where the line attaches to the fuel tank.
This valve prevents gasoline from sy phon ing out of
the fuel tank should a line rupture. See Figure I2 for
anti-syphon location.
Figure I2: Fuel Tank Fittings
The fuel withdrawals are positioned in the fuel
tanks to achieve optimum fuel usage, and fuel
line routing. At certain speeds and hull trim
angles, the fuel supply at the withdrawal tank
location can increase or decrease accord-
ingly. Be extremely care ful when attempting to
operate the boat on a minimum amount of fuel.
Though some fuel may be in the tank, the rela-
tive trim angle of the boat may cause the fuel
to flow away from the with drawal.
NOTICE
Access plates or lids are provided in the floor
for easier access to the fuel pick-up, anti-sy-
phon valve and send er.
D. Fuel Gauge
The fuel gauge indicates the amount of fuel in the
tank. See Section E-7F - Fuel Gauge for addition al
information on fuel gauge use.
E. Fuel Senders
The fuel sender consists of a float which travels up
and down a stationary tube. The float measures the
level of the fuel in the tank and sends a signal to the
fuel gauge. See Figure I3.
Fuel Systems - Section I
Figure I3: Fuel Sender Operation
Due to the mechanical nature of the fuel sender,
variations in readings during various speeds of
operation may occur. This system is merely a relative
indication of the avail able fuel supply and not a
calibrated instru ment. With this type of sending unit
a more accurate measurement of fuel level is obtained
with the boat in a level position.
The gauge readings will also vary with the trim angle
of the boat. When sitting at a dock and the boat is
nearly level, the fuel gauge will register accurately.
Refer to Figure I3. When boating, the trim angle of the
boat changes and affects the gauge readings. Under
these conditions, the fuel sender will register "full" for
the first few hours of running time until the fuel level
drops below the 3/4 or 1/2 mark. This is caused by
the angle of the fuel in the tank as shown in
Figure I4.
Figure I4: Effects of Trim Angle
It is very important to keep track of hours and fuel
consumption to obtain an average gallon per hour
consumption figure. Refer to the fuel log located at
the back of this manual. This will help to prevent any
prob lems with running out of fuel on the water.
Dealers are equipped with some general figures on
consumption which can be used as a guide until spe-
cific information on your boat is deter mined. Because
of boating conditions, speed, weight and other factors
common to your situa tion, fuel consumption will vary
between your boat and consumption figures devel-
oped by Four Winns.
Owner's Manual Page 74