Garmin 90/140 User manual

Owner’s Manual
Fishfinder 90/140

© 2006 Garmin Ltd. or its subsidiaries
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Garmin Corporation
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Taiwan
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Fax [phone]
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August 2006 Part Number 190-00582-00 Rev. B Printed in Taiwan

Fishfinder 90/140 Owner’s Manual iii
INTRODUCTION > ABOUT THIS MANUAL
INTRODUCTION
This manual covers the features and operation of the
Fishfinder 90/140.
About This Manual
To get the most out of your Fishfinder 90/140, take time to
read this manual and learn the operating procedures for your
unit in detail. This manual is organized into the following
sections.
The Introduction sections contains the Table of Contents,
Product Registration, and Product Support Information.
The Getting Started sections contain information about
sonar and the Fishfinder.
The Installing Your Fishfinder section provides instruction
on installing the Fishfinder and the Transducer. If you
experience difficulty installing the Fishfinder, contact
Garmin Product Support or an installation professional in
your area.
The Operating Your Fishfinder section describes the
features and operation of the Fishfinder 90/140.
The Appendix contains unit specifications ,optional
accessories, and care information. You can also find
warranty information, the Software License Agreement and
European Licensing Requirements in the Appendix.
An Index is provided at the end of the manual for reference.
Manual Conventions
This manual uses the term Warning to indicate a potentially
hazardous situation, which, if not avoided, could result in
death or serious injury.
This manual uses the term Caution to indicate a potentially
hazardous situation, which, if not avoided, may result
in minor injury or property damage. It may also be used
without the symbol to alert you to avoid unsafe practices.

iv Fishfinder 90/140 Owner’s Manual
INTRODUCTION > TABLE OF CONTENTS
TABLE OF CONTENTS
Introduction ...........................................................iii
Manual Conventions .....................................................iii
Product Registration ................................................ v
Contact Garmin .............................................................. v
Warning ....................................................................vi
Getting Started .......................................................1
Understanding the Fishfinder ................................. 1
Understanding Sonar ..................................................... 1
Understanding Dual Beam Transducer Coverage ......... 2
Understanding the Fishfinder Screen ............................. 3
Using Simulator Mode .............................................4
Installing Your Fishfinder .....................................5
Installing the Transducer ......................................... 6
Mounting the Transducer on a Transom ........................ 7
Installing the Fishfinder Unit ................................. 10
Selecting a Fishfinder installation Location ................ 10
Mounting the Bracket Assembly ................................. 10
To install the Fishfinder on the mount bracket: ........... 11
Installing the Wiring Harness ................................ 12
Testing the Transom Mount Installation ............... 13
Operating Your Fishfinder ..................................14
Understanding Basic Functions ........................... 14
Using the Main Menu .............................................15
Options and Settings .................................................... 15
Using the Setup Menu ............................................16
Options and Settings .................................................... 16
Appendix ..............................................................19
Specifications ......................................................... 19
Fishfinder 90 ................................................................ 19
Fishfinder 140 .............................................................. 19
Fishfinder 90 and Fishfinder 140 ................................. 19
Optional Accessories ............................................. 19
Caring for the Fishfinder .......................................20
Cleaning the Case ....................................................... 20
Cleaning the Screen ..................................................... 20
Storage ......................................................................... 20
Water Immersion ......................................................... 20
Software License Agreement ................................ 21
Limited Warranty .................................................... 21
Declaration of Conformity (DoC) ..........................23
Tell Us What You Think .............................................. 23
Index .....................................................................24

Fishfinder 90/140 Owner’s Manual v
INTRODUCTION > PRODUCT REGISTRATION
Product Registration
Help us better support you by completing our online
registration today! Connect to our Web site at www.garmin.
com/registration/.
Use this area to record the serial number (8-digit number
located on the back of the Fishfinder 90/140) in case your
Fishfinder 90/140 needs service. Keep the original sales
receipt, or a photocopy, in a safe place.
Serial Number: ___ ___ ___ ___ ___ ___ ___ __
Contact Garmin
Contact Garmin if you have any questions while using
your Fishfinder 90/140. In the USA contact Garmin
Product Support by phone: [phone] or 913/397.8200,
Monday–Friday, 8 AM–5 PM Central Time; or go to www.
garmin.com/support/, and click Product Support.
In Europe, contact Garmin (Europe) Ltd. at
[phone] (outside the UK) or
0870-8501242 (UK only).

vi Fishfinder 90/140 Owner’s Manual
INTRODUCTION > WARNING
Warning
WARNING: This product, its packaging, and its components contain chemicals known to the State of California to cause cancer, birth
defects, or reproductive harm. This Notice is being provided in accordance with California’s Proposition 65. If you have any questions or
would like additional information, please refer to our Web site at http://www.garmin.com/prop65.
Failure to avoid the following potentially hazardous situations could result in an accident or collision resulting in death or
serious injury.
When navigating, carefully compare information displayed on the Fishfinder 90/140 to all available navigation sources, including
information from visual sightings, and maps. For safety, always resolve any discrepancies or questions before continuing navigation.

Fishfinder 90/140 Owner’s Manual 1
GETTING STARTED > UNDERSTANDING THE FISHFINDER
GETTING STARTED
To get the most out of your new Fishfinder:
• Before you install and use your Fishfinder, read the
information in this manual.
• Assemble and install the hardware (page 5).
• Practice using your Fishfinder in Simulator Mode
(page 4).
• Use the Fishfinder (page 13).
Understanding the Fishfinder
The Fishfinder 90 or 140 is a fully automatic sonar unit
that allows you to go out on the water and find fish without
having to configure a lot of settings; or, if from experience
you know exactly how you want your Fishfinder screen to
look and function, you can customize each setting to your
specific needs.
If you have used a Fishfinder before, and you know how
to interpret the sonar information on the screen, you can
skip this section. If you have not used a Fishfinder before,
you might want to learn a bit about sonar: what it is, how it
works, and what you might see on the Fishfinder 90 or 140
screen. This manual does not go into technical detail about
sonar, but it can give you a general understanding of those
things that you need to know about sonar that can help you
interpret the screen and find the fish.
Understanding Sonar
During installation, you connect your Fishfinder 90 or 140
to a transducer. The transducer uses sound to determine
information about what is in the water beneath your boat.
Then the transducer sends the information to your Fishfinder
to be displayed on the screen for you to view and interpret.
The transducer sends sound waves down into the water
in a cone shape, similar to a flashlight beam (covering a
smaller circular area at the top and angling out to a larger
circular area at the bottom). These sound waves reflect off
of any object that they hit, and then the waves travel back
up to the transducer. These objects could be fish, branches,
the bottom, or any other object that has density that is
different from the water. The transducer receives the sound

2 Fishfinder 90/140 Owner’s Manual
GETTING STARTED > UNDERSTANDING DUAL BEAM TRANSDUCER COVERAGE
wave information, and then sends the information to the
Fishfinder. The Fishfinder displays the information on the
screen for you to see and interpret. The type of transducer
and settings you choose determine how the information is
shown on the screen.
Understanding Dual Beam Transducer
Coverage
A dual beam transducer can transmit a narrow or a wide
beam. The water area covered by the transmitted sound
waves is determined by the beam width of the transducer
and the water depth. The narrow beam provides crisp detail
of what is under your boat, and is helpful if you are fishing
in deeper water where the beam covers more area (for
example, at a 30-foot depth, the narrow beam covers the
area of about a 7-foot circle).
Wide
Beam
Narrow
Beam
The wide beam is more helpful in shallow water, because
it gives you a much wider view of objects in the water,
including areas beyond the sides of your boat. At a 30-foot
depth, the wide beam covers the area of approximately a
20-foot circle.

Fishfinder 90/140 Owner’s Manual 3
GETTING STARTED > UNDERSTANDING THE FISHFINDER SCREEN
Understanding the Fishfinder Screen
Experimentation and experience are the keys to successfully
interpreting your Fishfinder screen. We recommend that you
take your Fishfinder out on familiar water, and spend time
learning to interpret what you see on the Fishfinder 90 or
140 screen.
Think of the Fishfinder screen as if you took a picture
from the side of an aquarium in your home. You can see
how deep a fish is in the water (how close it is to the top
or bottom), but you cannot tell where the fish is located
horizontally in the water (whether it is near the front or the
back of the aquarium). Remember this when you are trying
to locate exactly where something is in the water.
Water depth Depth range
Water
temperature at
the transducer
You see
suspended targets
as arches or fish
symbols.
Structure
Bottom shape and type
Simulator
mode
indicator
The strongest sonar returns appear on your screen as solid,
dark areas. The weakest returns appear less intense, less
solid. The bottom of the water body returns the strongest
signal, so you can identify the bottom as the continuous,
solid line running across the bottom of the screen. The
strength of the sonar return can also help you interpret the
hardness of the bottom. The thicker the bottom line, the
harder the bottom.

4 Fishfinder 90/140 Owner’s Manual
GETTING STARTED > USING SIMULATOR MODE
The Fishfinder 90 and 140 include the latest technology
in interpreting bottom signals; they can see through fish,
structures, and thermoclines (shown in the weakest hues).
Even so, large schools of fish or dense structures close to
the bottom can affect water depth return readings.
NOTE: If the Fishfinder is unable to track the bottom
for any reason, the digits which indicate depth flash on
and off to alert you that the Fishfinder is not tracking
the bottom.
Along the top of the screen, you might see a grouping of
intense hues. This area is surface clutter, which can be
caused by waves or any other sonar interference at the
surface of the water. Too much surface clutter can obscure
your view of fish. You can turn down the Gain setting to
reduce this surface clutter (Page 14).
You can see in the previous illustration how the fish are
indicated in a few different ways. By default, fish appear
as arches. Actual fish returns might not always appear as
perfect arches, due to the speed, fish orientation, or other
conditions. You can also turn on the Fish Symbols setting if
you want to see suspended targets indicated by a fish shape
instead of arches (Page 16).
Using Simulator Mode
Use Simulator Mode to practice and learn the operation of
the Fishfinder. If the Fishfinder does not detect a transducer
at startup, it automatically starts in Simulator Mode.
While in Simulator Mode, the Fishfinder displays a bottom
scene, and you can control the Fishfinder (except the Gain
and Auto Gain options) just as if it were on the water.
If no keys are pressed for two minutes, the Fishfinder
automatically resets to default settings while in Simulator
Mode.
To exit Simulator Mode, turn off the Fishfinder.

Fishfinder 90/140 Owner’s Manual 5
INSTALLING YOUR FISHFINDER > PACKING LIST
INSTALLING YOUR FISHFINDER
Make sure you completely read and understand all
instructions before you install and use your Fishfinder. If
you have problems, contact Garmin Product Support, or
seek other professional assistance.
You can install the Fishfinder hardware on a transom or on
a trolling motor. Before installation, make sure the wiring
harness can reach the Fishfinder and transducer locations.
Check the packing list below. If you are missing any items,
contact your Garmin dealer.
Packing List (one of each, unless otherwise noted):
A—Fishfinder sonar unit
B1—Swivel mount bracket (Fishfinder
140; optional for Fishfinder 90); or
B2—Tilt mount bracket (Fishfinder 90)
C—Swivel base (Fishfinder 140)
D—Mounting knobs
E—Mounting knob spacer
F—Snap ring
G—Transducer with power cable
H—Transducer mount
I—Trolling motor mount gasket
J—5 mm Flat washers (2)
K—5 x 30 mm Screws (2)
L—10-32 Lock nut
M—4 x 12 mm Screws (4)
N—10-32 x 1.75 Screw
O—1/4" Cable clamps (2)
P—Plastic spacer
Q—1/4" Rubber washer
R—Cable tie, 5.6" (4)
S—Cable tie, 20”
J
K
L
M
N
O
P
Q
R
I
S
G
(Cable not shown)
C
D
E
B1
F
(Fishfinder 90)
B2
(Fishfinder 90)
(Fishfinder 140)
A
H

6 Fishfinder 90/140 Owner’s Manual
INSTALLING YOUR FISHFINDER > INSTALLING THE TRANSDUCER
Installing the Transducer
Assembling the Transducer
1. Insert the rubber washer (Q) and plastic spacer (P)
into the transducer (G) at the same time. DO NOT
lubricate the rubber washer.
2. Route the cable toward the back of the transducer.
Slide the transducer into the transducer mount (H).
3. Place a 5 mm flat washer (J) on the 10-32 x
1.75" screw (N), and insert the screw through the
transducer mount, spacer, and rubber washer.
4. Place the remaining 5 mm flat washer on the
exposed end. Install the 10-32 lock nut (L) finger
tight. You can tighten the transducer further after
installation on the boat.
Mounting the Transducer on a
Trolling Motor
1. Slide the large cable tie (S) through the slot on the
transducer mount (H) with the ridges of the band
facing up until equal lengths extend on both sides of
the mount. (NOTE: For cold water, or heavy timber
or debris areas, a metal 4-5" worm gear clamp is
recommended.)
2. Position the mount gasket (I) on the curved top of
the transducer mount.
3. Place the transducer assembly
against the motor body of the
trolling motor, with the front
of the transducer pointed
away from the trolling motor
propeller.
Back of the transducer Cable tie
slot

Fishfinder 90/140 Owner’s Manual 7
INSTALLING YOUR FISHFINDER > INSTALLING THE TRANSDUCER
4. Wrap the two ends of the cable tie around the motor
body. Place the pointed end of the cable tie through
the fastener hole on the opposite end and pull it
through until it is snug but not tight. (The cable tie
clicks when you pull it.)
5. Position the transducer so that it is parallel with the
bottom when in use, and make sure the gasket is
aligned properly. Pull the cable tie end until tight.
Trim off the excess, if necessary. Tighten the 10-32
locking nut until it touches the mounting bracket and
then tighten 1/4 turn more. (Do not overtighten.)
6. Route the 20’ (6 m) transducer cable using the
supplied cable ties to secure the cable to the motor
shaft. You can fill the forward-facing portion (except
the cable tie pocket) of the transducer mount with
sealant to avoid accumulating debris.
Mounting the Transducer on a Transom
Tool List (not included)—drill, 3/8" wrench or socket,
5/32" and 1/8" drill bits, masking tape, #2 Phillips
screwdriver, and marine sealant.
When selecting a transom mount location, consider the
following for optimal performance:
• For your sonar to operate properly, the transducer
must be located in calm water. DO NOT mount the
transducer behind strakes, rivet lines, struts, fittings,
water intake, discharge ports, eroding paint, or
anything that creates turbulence.
• Mount the transducer as close to the center of the boat
as possible.
• DO NOT cut the transducer lead. (This voids your
warranty.)
• DO NOT mount the transducer in locations where it
might be jarred when launching, hauling, trailering,
or storage.

8 Fishfinder 90/140 Owner’s Manual
INSTALLING YOUR FISHFINDER > INSTALLING THE TRANSDUCER
• DO NOT mount the transducer in the path of the
prop on single-drive boats. The transducer can cause
cavitation that can degrade the boat’s performance
and damage the prop. On twin-drive boats, mount
the transducer between the drives, if possible.
Do not mount the transducer behind
strakes, rivet lines, struts, fittings, water
intakes or discharge ports.
Mount the transducer
parallel with the water line.
Make sure the transducer is below
water level when the boat is on plane
at high speed.
Apply marine sealant to all screw threads to prevent
water from seeping into the transom.

Fishfinder 90/140 Owner’s Manual 9
INSTALLING YOUR FISHFINDER > INSTALLING THE TRANSDUCER
To mount the transducer on a transom:
1. Position the transducer mount at the selected
transom location. Make sure the transducer is
parallel with the water line. Mark the center locations
of each hole on the transducer mount. (See the
figures on the next page.)
2. Using a 5/32" bit, drill the pilot holes approximately
1" (25 mm) deep at the marked locations. To avoid
drilling the holes too deep, wrap a piece of tape
around the bit at 1" from the point of the bit.
3. Apply marine sealant to the 5 x 30 mm screws.
Attach the transducer assembly to the transom
using the 5 x 30 mm screws. Adjust the transducer
assembly to extend beyond the bottom of the
transom approximately 1/8" (3 mm) on fiberglass
hulls or 3/8" (10 mm) on aluminum hulls. Adjust the
transducer assembly to be aligned parallel with the
water.
4. Tighten the 10-32 locking nut until it touches the
mounting bracket, and then tighten 1/4 turn more.
(Do not overtighten.)
5. Place the first cable clamp on the transducer cable
approximately one third of the distance between
the transducer and the top of the transom. Mark
the location. Using a 1/8" bit, drill a pilot hole
approximately 3/8" (10 mm) deep.
6. Attach the cable clamp using a 4 x 12 mm screw.
Coat the screw with marine sealant before
installation. Repeat steps 5 and 6 using the other
cable clamp.
7. Route the transducer cable, as needed, to the
Fishfinder. DO NOT CUT THE CABLE. Avoid routing
the cable with electrical wires or other sources of
electrical interference.

10 Fishfinder 90/140 Owner’s Manual
INSTALLING YOUR FISHFINDER > INSTALLING THE FISHFINDER UNIT
OK
Level
Drill pilot holes here.
Vertical
Bottom of the transom
Align with the
transom bottom. The
transducer should
extend 1/8" below
fiberglass hulls or
3/8" below aluminum
hulls.
Keep it parallel with the water line.
Installing the Fishfinder Unit
Selecting a Fishfinder installation Location
Select a Fishfinder installation location that allows you to
view and operate it easily while operating the vessel. Select
a mounting surface strong enough to support the weight
of the Fishfinder and protect it from excessive vibration or
shock. DO NOT mount the bracket in a location where the
Fishfinder is exposed to extreme temperature conditions.
When installing the mounting bracket, be sure to allow
room to connect and rout the power cable.
Mounting the Bracket Assembly
Tool List (not included)—drill, screwdriver (Phillips or
standard), three #8 pan-head machine bolts with matching
nuts and washers, and a 5/32" drill bit; or three #8 pan-head,
self-tapping screws and a 1/16" drill bit.

Fishfinder 90/140 Owner’s Manual 11
INSTALLING YOUR FISHFINDER > INSTALLING THE FISHFINDER UNIT
(Fishfinder 90)
Tilt mount bracket
To mount the bracket assembly:
1. Using the tilt mount bracket (Fishfinder 90) or the
swivel base (Fishfinder 140; Fishfinder 90 option)
as a template, mark the location of the three holes
that you use to secure the bracket to the mounting
surface.
2. If securing the base with machine bolts, drill three
5/32" holes at the locations you marked; or, if
securing the base using self-tapping screws, drill
1/16" starter holes at the locations you marked. Drill
starter holes no deeper than half the screw length.
3. Secure the tilt mount bracket or swivel base with
three bolts or screws. DO NOT OVERTIGHTEN.
4. If you are using the swivel mount, place the swivel
mount bracket over the swivel base and secure it
with the short knob.
To install the Fishfinder on the mount bracket:
1. Align the slot on the back of the Fishfinder with the
long mounting knob, and slide the Fishfinder into
place. If necessary, adjust the long knob to spread
the bracket arms apart. (Turn counter-clockwise to
widen the bracket arms and clockwise to tighten.)
2. Adjust the Fishfinder angle, and tighten the long
mounting knob until snug.
3. For the Fishfinder 140 (Fishfinder 90 option), rotate
the swivel mount bracket by twisting it left or right.
The bracket clicks as you turn it. Select a good
viewing angle, and then tighten all knobs.
Swivel mount bracket
(Fishfinder 140;
Fishfinder 90 option)
Swivel base

12 Fishfinder 90/140 Owner’s Manual
INSTALLING YOUR FISHFINDER > INSTALLING THE WIRING HARNESS
Installing the Wiring Harness
The Fishfinder comes with a wiring harness that connects
the Fishfinder to power and the transducer with one
easy-to-remove connection. If it is necessary to extend the
power wires, use 22 AWG wire. DO NOT cut the transducer
cable, because this voids your warranty. If your boat has an
electrical system, you might be able to wire the Fishfinder
directly to an unused holder on your current fuse block. If
you are using the boat’s fuse block, remove the in-line fuse
holder supplied with the Fishfinder. You can also wire the
Fishfinder directly to the battery.
CAUTION: The Fishfinder input voltage is 10–18
volts DC. Do not exceed this voltage, because this can
damage the Fishfinder and void the warranty.
To install the wiring harness:
1. Determine the polarity of the power source using a
test light or volt meter.
2. Install the red (+) wire on the positive fuse holder or
battery terminal.
3. Install the black (-) wire on the negative fuse holder
or battery terminal.
4. Install a 2 Amp fuse in the fuse holder (fuse block
only).
5. Align the notches on the cable plug and on the back
of the Fishfinder. Insert the cable into the connector
and turn the lock ring counter-clockwise until it stops.

Fishfinder 90/140 Owner’s Manual 13
INSTALLING YOUR FISHFINDER > TESTING THE TRANSOM MOUNT INSTALLATION
Testing the Transom Mount
Installation
Perform this test after you install the Fishfinder. Because
you need water to carry the sonar signal, the Fishfinder
does not function properly with the transducer out of the
water. When you place your boat in the water, CHECK FOR
LEAKS around the screw holes that are below the water
line. DO NOT leave your boat in the water for an extended
period of time without checking for leaks.
To test the transom mount installation:
1. Begin testing the installation at a slow speed. If the
sonar appears to be working properly gradually
increase the boat’s speed observing the sonar’s
operation. If the sonar signal suddenly is lost or the
bottom return is severely degraded, note the speed
at which this occurs.
2. Return the boat to the speed at which the signal was
lost. Make moderate turns in both directions, and
see if the signal improves.
3. If the signal strength improves while turning, adjust
the transducer so that it extends another 1/8"
below the transom of the boat. It might take several
adjustments to eliminate the degradation.
4. If the signal does not improve, it might be necessary
to move the transducer to a different location.

14 Fishfinder 90/140 Owner’s Manual
OPERATING YOUR FISHFINDER
ENTER
MENU
Power key—turns the Fishfinder on or
off and controls the screen backlight.
(Fishfinder 140 is shown.)
ENTER key—confirms a selection.
MENU key—shows or exits a menu.
Arrow keys—the up and down Arrow
keys select an item on a menu. Only
the Fishfinder 140 has the right and left
Arrow key that cycles through the Main
menu options.
Understanding Basic Functions
To turn on the Fishfinder:
Press and release the Power key.
To turn off the Fishfinder:
Press and hold the Power key.
To change the backlight level:
Press the Power key repeatedly to cycle between off,
low, and high.
To view or change settings for your Fishfinder, use the Main
menu and the Setup menu.
To change a setting:
1. Press MENU. The Main menu appears.
2. Use the Arrow keys to move the selection arrow to
an option, and press ENTER. The settings appear.
If you select Setup, the Setup menu appears. See
“Using the Setup Menu” on page 16.
OPERATING YOUR FISHFINDER > UNDERSTANDING BASIC FUNCTIONS