2. The fishfinder won’t turn of f:
The fishfinder may have been wire d for
Auto power. In this case, the fishfinder
cannot be turned off while the ign ition
power is on. (See Auto power wiring in
section 6-5 Wiring options. )
3. The fishfinder operates erratically:
a) Check that the transducer does no t have
debris (e.g. weed, plastic bag) ca ught
around it.
b) The transducer may have been damaged
during launching, running agroun d or while
underway with debris etc. If the tra nsducer
has been impacted, it may have been ki cked
up on the bracket. If it is not physically
damaged, reset the transducer back to
its original position. (See the Tr ans om
Transducer Installation Guide.)
c) When the transducer is less t hat 2 ft. (0.6 m)
from the bottom, the depth readings m ay
become inconsistent and erratic.
d) Manual Gain may be set too low, which may
cause weak bottom echo or no fish sig nals. If
in Manual Gain, try increasing the G ain.
e) Ensure the back of the bottom sur face 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 gener ation
of bubbles through cavitation. (S ee the
Transom Transducers Installation Guide.)
f) Check the tr ansducer and power ca ble
connectors at the back of the display unit
are securely plugged in and the collar s are
locked in place. The collars must be se cure
for watertight connection.
g) I nspect the power ca ble from end to end
for damage such as cuts, breaks, squ ashed
or trapped sections.
h) Ensure there is not another fishfinde r
or depth sounder turned on, which may
interfere with this fishfinder.
i) Elec trical noise from th e boat’s engine
or an accessory may be interfering with
the transducer(s) and/or the Navman
fishfinder. This may cause the fish finder
to automatically decrease the Gain unless
using Manual Gain.
The fishfinder thus eliminate s weaker
signals such as fish or even the bottom
from the display. This may be checked
by switching off other instrument s,
accessories (e.g. bilge pump) and the moto r
until the offending device is located . To
stop problems from electrical noise, try:
- re-routing the power and transducer
cable(s) away from the boat’s other
electrical wiring.
- routing the display unit’s power cable
directly to the battery with an in -line
fuse.
4. Bottom is not displayed:
a) The fishfinder may have Manual R ange
selected and the depth may be outsi de the
range value selected. Either chan ge the
fishfinder to Auto Range or selec t another
depth range (see section 4-5 Ra nge).
b) T he depth may be outsid e the fishfinder ’s
range. While in Auto Range, the display unit
will display “--.-” to indicate that there is no
bottom detected. A display of the bot tom
should reappear when in shallower water.
5. The bottom is displayed too far up
the screen:
The fishfinder may have Manual Rang e
selected and the selected Ra nge value is
too high for the depth. Either change the
fishfinder to Auto Range or selec t another
depth range (see section 4-5 Ra nge).
6. Bottom echo disappears or erratic
digital reading while the b oat is moving:
a) Ensure the back of the bottom surf ace
of the transducer is slightly lower than
the front and the front is as deep in the
water as possible in order to minimise the
generation of bubbles through cavitation.
(See the Transom Transducers Installation
Guide, for more information.)
b) T he transducer may be in turb ulent water.
Air bubbles in the water disrupt the echoe s
returned, interfering with the f ishfinder’s
ability to find the bottom or othe r targets.
This often happens when the boat is
reversed. The transducer must be mounte d
in a smooth flow of water in order for the
fishfinder to work at all boat spee ds.
c) Electrical noise from the b oat’s motor can
interfere with the fishfinder. Try some
suppression spark plugs.
FISH 4432/4433 Installation and Operation Manual 36
NAVMAN