Operation Manual

8120 Installation and Operation Manual63
Clear Used
Select Clear used to set Used (the
amount of fuel used) to zero. Do this to start
measuring how much fuel is used during a
trip (see section 12-2 Used)
Tank size
Enter the capacity of the fuel tank. Navman
recommends measuring tank size by draining
the fuel tank, filling it to capacity and using
the fuel dispenser’s reading. Beware of air
pockets, especially in underfloor tanks.
Num engines
Set the number of engines to 0, 1 or 2. If 0
is selected the fuel features are turned off.
Calibrate
SmartCraft fuel sensors and Navman diesel
sensors are factory calibrated and should
never need recalibrating. Calibrating Navman
petrol/gasoline sensors gives more accurate
fuel values.
Twin engine installations require each fuel
transducer to be calibrated. This can be done
at the same time with two portable tanks or
at different times using one portable tank.
Calibrating the fuel transducer(s) requires
accurate measurement of the fuel
consumption. This is best done using a small
portable tank. At least 4 gallons (15 litres) of
fuel should be used to ensure an accurate
calibration.
It is often very difficult to fill underfloor tanks
to the same level twice due to air pockets, so
the more fuel used, the more accurate the
calibration.
To calibrate the fuel transducer(s), perform
the following steps:
1. Record the level of the fuel in the tank(s).
2. Connect the portable tank(s) to the engine
through the fuel transducer(s).
3. Run the engine at normal cruising speed
until at least 4 gallons (15 litres) of fuel has
been used per engine.
4. Check the actual amount of fuel used per
engine by refilling the portable tank(s) to
the original level and noting the reading(s)
from the fuel dispenser’s gauge.
5. Select Fuel. Use the cursor keys to
change the reading for each engine to
match that on the fuel dispenser’s gauge.
6. Press
ENTER
when the reading is correct.
Note: If the fuel calibration options appear
to give erroneous readings after a while, first
check that the fuel sensor has been installed
correctly according to the installation
instructions supplied with it, then see
Appendix B - Troubleshooting.
Flow filter
Most engines do not draw fuel from the tank
at a steady rate. To give a stable fuel flow
reading, the Instrument calculates the flow
value(s) by taking several measurements and
averaging them. Use the Flow filter to set the
period over which the fuel flow is averaged.
The Flow filter can be set from 0 to 30
seconds. Use the lowest value which gives a
stable flow. Usually a value of 5 to 10 seconds
will give a satisfactory result for two-stroke
carburettor engines. Fuel injected or four-
stroke engines may require a larger value.
This setting affects the Fuel flow and
Fuel economy reading on the Fuel
window but it does not affect the Fuel
used reading.
Fuel consumption curve
See section 12-3.
Diesel sensors
If the boat has twin diesel engines and
Navman diesel sensors, set up the diesel
sensors:
1 In the fuel setup menu, select Diesel
sensors.
2 The window
shows fuel
flow and
RPM for the
two engines.
Identify which
line has data
for the port
engine; for