Connecting a Tohatsu Engine to a Fishfinder Display

How to easily connect a Tohatsu engine to an NMEA 2000 system

Would you like to monitor your Tohatsu outboard data on a fishfinder or multifunction display? The ready-made Fimarin MC-BP-TO NMEA 2000 connection kit makes this simple and safe. In this blog post we go through how to make the connection – step by step.

Parts needed for the connection

Fimarin MC-BP-TO-4 and MC-BP-TO-2 kits contain everything you need:

• NMEA 2000 engine cable, 2 or 4 m – connects directly to the Tohatsu engine
• Backbone cable, 4 or 2 m – the network backbone
• 2 T-connectors – connect the devices to the backbone
• Power tap, male, 2 m, with fuse (5A) – power supply from the battery
• Terminators, male and female – at both ends of the system

The Fimarin Tohatsu NMEA 2000 MC-BP-TO-4 kit with a 4 metre drop cable is available here
The Fimarin Tohatsu NMEA 2000 MC-BP-TO-2 kit with a 2 metre drop cable is available here

The kits are available with either a 2 metre or a 4 metre engine cable.

Compatibility
The kit fits:

• All electric-start Tohatsu outboards of 40 hp and above with NMEA 2000 support from 2014 onwards
• 25 and 30 hp D models (2023–>), as long as they are electric start (DETL and DETS)
• For 25 and 30 hp C models, a separate adapter is available that attaches to the ECU:
  https://www.fimarin.fi/adapteri-mfs25c-ja-mfs30c-tohatsuihin

Unsure about compatibility? Contact Fimarin customer service – we are happy to help!

Bringing engine data to your fishfinder:

1. Engine connection

Connect the kit's engine cable directly to the Tohatsu engine's diagnostic port. The diagnostic port is typically on the left side of the engine, as in the picture below. Route the cable through the engine's rubber grommet.

On the Tohatsu 30D, the connector branches off the ECU wiring harness:

Example of connecting a Tohatsu 30D engine:

2. Building an NMEA 2000 Network

Build the NMEA 2000 network according to the diagram:

• Connect the power tap to the battery via the main switch. Make sure the main switch is in the off position.
• Connect the T-connectors on both sides of the power cable.
• Connect the cable coming from the engine to one T-connector and the cable going to the fishfinder to the other.
• Attach the terminators to both ends of the T-connector row.

Diagram of an NMEA 2000 system with a Tohatsu engine and a chartplotter connected:

3. Power connection

Connect the power tap to one of the T-connectors. Run the cable to the 12V battery and make sure that the positive wire between the battery and the NMEA 2000 system goes through the main switch. If the NMEA 2000 system is incorrectly connected directly to the battery, it can draw power even when the devices are in standby. The main switch prevents flat battery problems.

The power cable must include a fuse to protect the devices and the system. The Fimarin power tap and power cable come with a 5A fuse already fitted to protect the system.

4. Terminators

Fit the terminators at both ends of the backbone: male and female at their own ends. This is essential for the NMEA 2000 network to work correctly.

5. Connecting the display

Connect a compatible fishfinder or multifunction display to the other T-connector. Make sure your display has an NMEA 2000 standard Micro-C connector and NMEA 2000 compatibility. Compatible fishfinders can be found in our list: https://www.fimarin.fi/nmea-2000-yhteensopivat-kaikuluotaimet

Done! Time to head out on the water and try it!

Switch on the boat's main power and start the engine. Go to your fishfinder/display settings and check whether the engine appears as a device on the NMEA 2000 network. Not all displays necessarily recognise every Tohatsu engine. If your display does not recognise the engine, don't worry! Try adding engine data fields to the screen you want. Engine data is standardised and your display can read it automatically.

If engine data does not appear while the engine is running:
1. Check the connections.
2. Make sure the terminators are in place. The system will not work without the terminators.
3. Make sure the NMEA 2000 system receives 12V from the battery.
4. Check the cables and connectors for any damage.

Fimarin The MC-BP-TO kit makes the connection quick, reliable and tidy – without unnecessary hassle. With the right connectors and quality cables you avoid interference and get out on the water sooner.

Order the kit directly from the Fimarin online store and get engine data on your display with ease!