Garmin 300C - Manual

The Garmin Fishfinder 300C is a marine fishing sonar system designed for anglers requiring precise underwater mapping, depth sensing, and fish detection on boats. This installation manual covers essential topics like device setup, mounting methods–such as flush or bail mounts–and critical considerations for transducer placement to ensure accurate performance. Key areas include safety precautions, proper cable routing, power wiring, and compatibility with NMEA 0183 devices for seamless integration with GPS and other navigation systems. The guide emphasizes optimal positioning relative to the boat’s propeller and water flow to avoid interference while maintaining reliable sonar functionality.

Page 1 – Initial Setup and Mounting Guidance
Page 2 – Flush Mounting Procedures
Page 3 – Unit and Transducer Assembly
Page 4 – Transducer Mounting and Performance Warnings
Page 5 – Transom Transducer Installation Guidelines
Page 6 – Wiring Harness and Fuse Installation
Page 7 – NMEA Data Communication Setup
Page 8 – System Testing and Calibration

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Fishfinder 300C Installation Instructions

Compare the contents of this package with the packing list on the box. If any pieces are missing, contact your Garmin dealer immediately.

Before you begin the installation:

Read and follow the instructions to install the Fishfinder 300C.

Gather the appropriate fasteners and tools.

Verify that all cables can reach the Fishfinder 300C mounting location and the transducer.

Wear safety goggles and a dust mask when drilling, cutting, or sanding.

If you experience difficulty installing the Fishfinder 300C, contact Garmin Product Support or contact a professional installer.

WARNING

: See the

Important Safety and Product Information

guide in the product box for product warnings and other important

information.

To install and use your Fishfinder 300C:

1. Select a location.

2. Mount the Fishfinder 300C.
3. Install the transducer.
4. Install the wiring harness.

5. Test the installation.

Step 1: Select a Location for the Fishfinder 300C

Consider the following when you select an installation location:

Provide optimal viewing as you operate your vessel.

Allow easy access to the keypad on the Fishfinder 300C.
Is strong enough to support the weight of the Fishfinder 300C and protect it from excessive vibration or shock.
Allow room for the routing and connection of the cables. There should be at least a 3-inch (8 cm) clearance behind the case.

DO NOT mount the Fishfinder 300C in an area that is exposed to extreme temperature conditions.

NOTE:

The temperature range for the Fishfinder 300C is from 5°F to 131°F (from -15°C to 55°C). Extended exposure to temperatures exceeding this

range (in storage or operating conditions) may cause failure of the LCD screen or other components. This type of failure and related consequences are

not covered by the manufacturer’s limited warranty.

Step 2: Mount the Fishfinder 300C

You can mount your Fishfinder 300C in one of two ways:

Bail Mount—mount the Fishfinder 300C onto the bracket that attaches to the console or overhead.
Flush Mount—use the flush mount kit to mount the Fishfinder 300C into a flat panel.

Bail Mounting the Fishfinder 300C

The Fishfinder 300C is suitable for mounting in exposed locations or at the navigation station. The included tilt mounting bracket can be used

for console or overhead mounting. Bail mounting requires the following tools and hardware:

Three of the included number 8 (4.2 × 1.4 DIN7981) ANSI mounting screws
Phillips-head screwdriver (not included)
Drill and drill bit (not included)
Center punch and hammer (not included)

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December 2007

190-00864-03 Rev. B

Printed in Taiwan

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