B-4 sonar fishfinding problems – NorthStar Navigation Multi-Function Unit M84 User Manual

Page 106

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Northstar M121/M84 Installation and Operation Manual

105

3-2 Flow indicates no fuel or low fuel:

a Check that the number of engines is set to 1

(see section 19-6).

b Check that the fuel cable connectors are

securely plugged in and the collar is locked
in place. The collar must be locked in place
to give a watertight connection.

c A fuel transducer may be clogged. If so,

remove the transducer from the fuel line
and gently blow through it in the opposite
direction to the fuel flow.

A fuel filter between the fuel transducer and
the fuel tank must be installed as per the
fuel installation guide. Failure to do so will
void the warranty.

d Inspect the fuel cable from end to end for

damage such as cuts, breaks, trapped or
squashed sections.

e Check that the fuel filter is clean.

3-3 A twin engine installation shows only

one flow rate:

a Check that the number of engines is set to 2

(see section 19-6).

3-4 Erratic Fuel Flow readings:

a The fuel flow transducer may have been

mounted too close to the fuel pump or may
be subject to excessive vibration. Refer to
the installation instructions supplied with
the fuel transducer.

b Check for leaks in the fuel line or in the fuel

pickup in the tank.

c The

Flow filter value is not suitable for

the engine. Check that the value is not set
to zero, then try increasing the value until a
steady flow rate is shown (see section 19-6).

3-5 There is no reading for fuel economy:

a The boat must be travelling through the

water to generate an Economy reading.

b Check that the paddlewheel on the

transducer is spinning freely and that the
two magnets in the paddlewheel are still in
place.

B-4 Sonar fishfinding problems

4-1 The Instrument operates erratically:

a Check that the transducer does not have

debris (e.g. weed, plastic bag) caught
around it.

b The transducer may have been damaged

during launching, running aground or
while underway with debris etc. If the
transducer has been impacted, it may have
been kicked up on the bracket. If it is not
physically damaged, reset the transducer
back to its original position. (See the
Transom Transducer Installation Guide.)

c When the transducer is less that 2 ft (0.6 m)

from the bottom, the depth readings may
become inconsistent and erratic.

d Manual Gain may be set too low, which may

cause weak bottom echo or no fish signals. If
in Manual Gain, try increasing the Gain.

e Ensure the back of the bottom surface of

the transducer is slightly lower than the
front and the front is as deep in the water as
possible in order to minimize the generation
of bubbles through cavitation. (See the
Transom Transducers Installation Guide)

f Check the transducer and power cable

connectors at the back of the display unit
are securely plugged in and the collars are
locked in place. The collars must be secure
for watertight connection.

g Inspect the power cable from end to end for

damage such as cuts, breaks, squashed or
trapped sections.

h Ensure there is not another fishfinder or

depth sounder turned on, which may
interfere with this Instrument.

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