User Manual

Finding the Cause of Noise

Electrical noise usually affects the display with many black dots at high speeds,

and high sensitivity readings. One or more of the following sources can cause

noise or interference:

Possible Source of Noise Isolation

Turn off any nearby electronic devices to see

if the problem goes away, then turn them on

one at a time to see if the noise re-appears.

To determine whether the boat’s engine is

the source of the noise, increase the RPMs

while the boat is in neutral and stationary to

see if the noise increases proportionately; if

noise appears when you rev the engine, the

problem could be the spark plugs, alternator,

or tachometer wiring. Replace the spark

plugs with resistor plugs, install an alternator

filter, or route the control head power and

transducer cables away from the engine

wiring.

Turbulence created by the propeller can

cause noise; make sure the transducer is

mounted at least 15” (38 cm) from the

propeller, and that the water flows smoothly

over the face of the transducer at all times.

Other electronic devices

The boat’s engine

Cavitation from the boat’s

propeller

Troubleshooting