CONTINUOUSWAVE

On my recently purchased 1986 MONTAUK 17 with Evinrude E-TEC 90-HP engine there is a small white box that connects to the engine, some gauges, and the battery. I think this may be something for NMEA-2000.

Q1: what is the actual purpose of the small white box I have found on my recently purchased 1986 MONTAUK 17?

Q2: does the little white box allow [something] to be displayed on a chart plotter and fish finder combination device?

farnsrocket wrote:Q1: what is the actual purpose of the small white box I have found on my recently purchased 1986 MONTAUK 17?

There is nothing about a NMEA-2000 network that tends to required a small white box to be used.

Generally a NMEA-2000 network is assembled using pre-made molded cables and wiring appliances that are designed to fitted together without the need for the assembler needing to fabricate any sort of enclosure ("box"). Nor does the color of the box ("white") convey any significance. Typically the NMEA-2000 cables will have black insulation.

In order to allow readers to better reply to your question, you should post a close-up photograph of the "white box". This may allow readers to deduce something about it use or function from a visual identification. Also, include the text of any markings on the box that may not be seen in a photograph.

farnsrocket wrote:Q2: does the little white box allow [something] to be displayed on the GPS/fishfinder?

Again, there is no basis to make a proper answer to this question as the little white box is completely unknown to readers.

Regarding display of data on a chart plotter, if you can identify the brand and model of the chart plotter then readers would be better able to respond to your inquiry. Most modern multi-function displays can show a data they receive via the NMEA-2000 protocol connection. However, the E-TEC engine also sends NMEA-2000 data in proprietary datagrams that cannot be displayed on a generic multi-function display. For this reason, use of an Evinrude-branded NMEA-2000 display device may be more effective at providing all the engine data being sent.

If you are not familiar with the NMEA-2000 communication protocol, you should read my article in the REFERENCE section on the topic of

NMEA-2000 Networks and Modern Outboard Engines
https://continuouswave.com/whaler/refer ... A2000.html

This article explains in detail all the essential elements of construction of a NMEA-2000 network and connection of a modern outboard engine. As it happens, your Evinrude E-TEC 90-HP engine provides a NMEA-2000 network port. That engine is capable of transmitting a great deal of information about itself and other parameters to the NMEA-2000 network. Many modern multi-function display devices with a NMEA-2000 interface are capable of display data about engines.

Please submit a photo.

M

[Moderator's note: I added two in-line images after cropping them and applying exposure correction from the original, much larger but poorly exposed images.]





[Original images from]
https://imgur.com/a/qi9eIZk

The previous owner said the box is a "Captn NEMA" [sic] and I could read about it on "Golden Channels."

The purpose is to provide a wireless data link to a [smartphone] or personal computer with engine RPM and hours.

I'll have to do some research and see what it is all about. It sounds like it is similar to a Bluetooth vehicle OBDII reader.

Thanks everyone for your responses.

In the Figure 2, the connection of the small white box device to the network is incorrect. The device is connected to a Bus port on the network T-connector. It should be connected to the Device port of the network T-connector.

It probably works as it is connected, but that is not the correct way to do it.

The term "NEMA" has no application to the digital communication protocol used on boats, NNEA-2000.

I found product information about the small white box device at

https://goldenchannels.com/product/capn-nmea/

The product is not like an automotive ODB reader. The ODB port exists due to a federal regulation and auto manufacturers are required to provide it. Most after-market "readers" can display a huge amount of data. This "CAPN NMEA" device can only display engine speed in RPM and engine hours, unless you pay additional fees to upgrade it.

The manufacturer extols the value of the device as diagnostic tool. I really don't see much value in it for that purpose, as the diagnostic function is limited to the illumination of three LED indicator lamps.

There are additional tiers of utility that can be added to the device to enable logging. You can also purchase analysis of the logged data by the manufacturer.

As for transmitting data wirelessly to another device, it appears to be limited to engine RPM and hours. Also, some sort of application on the external device will be necessary to purchase to enable the external device to read the data.

The network as seen in Figure 2 appears to have only two connected devices. There could not be a more simple arrangement. Without knowing anything about the display device that is on the boat, to know what data that display can show is impossible to say. However, typical NMEA-2000 multi-function displays can show much more data that just engine RPM and engine hours.

The Evinrude E-TEC engine interface is very simple; it only requires the appropriate cable as the at the engine the connector is not the standard NMEA-2000 DeviceNet Micro connector. However, the previous owner probably has already purchased and installed the cable if he reports being able to see any engine data.

The situation with Evinrude is much more straightforward than with other engine brands like Mercury, Yamaha, or Suzuki. All of those have much more complicated wiring arrangements.