Northstar
EXPLORER 550/550i
Installation and Operation Manual
35
Now, do not change the engine speed.
Wait for about 60 seconds for the boat to
stabilise, then press
. Wait while the fuel
computer records the data.
7 The EXPLORER then asks you to set the
throttle to achieve a target RPM. On a multi
engine boat set all engines to about the
target RPM. When the engine RPMs are
correct, the Target RPM box will turn green.
Now, do not change the engine speed.
Wait for about 60 seconds for the boat to
stabilise, ensuring the Target RPM box stays
green. Then press
. Wait while the fuel
computer records the data.
8 The EXPLORER repeats the above step to
record data up to the maximum RPM. Then
the EXPLORER asks if you want to save the
curve. Select Yes. The fuel computer asks for a
name for the curve. Change the default name
if required. Then press
. The EXPLORER
stores the new curve.
Note
To interrupt making the curve at any time,
press
.
10-6-1 Making a fuel consumption curve
To make a fuel consumption curve you will need
to run the boat in a straight line for about 15
minutes using the engine’s full RPM range. For
your first curve, choose a calm day with light
wind and little current; have a typical load and
a freshly cleaned hull. Later, you can make fuel
consumption curves for different boat, weather
or sea conditions. Compare these with your
first curve to see how your boat’s performance
changes with conditions.
Making a curve
1 Start running the boat in a straight line.
2 Choose a speed source for the curve (see
section 10-5-1). Normally choose Water speed
to measure the boat’s potential performance.
3 Press
one or more times to display
the Setup menu, then select Fuel.
4 Select Fuel consumption curve, then select
New.
5 Enter the comfortable maximum RPM you
know you can achieve for the engine rather
than the maker’s value.
6 The EXPLORER then asks you to set the
minimum RPM. Set the throttle to idle; on a
multi engine boat set all engines to about the
same idle RPM.
10-6 Fuel consumption curves
A fuel consumption curve shows fuel consumption (fuel used per unit of distance travelled) and boat
speed as a function of engine RPM. Fuel consumption curves require engine RPM, which requires
SmartCraft sensors to be installed. Fuel consumption curves are powerful tools for assessing boat
performance in different conditions and for helping you to run at the most economical speed for the
conditions.