Adding Mercury NMEA 2000 Gateway to 2004 Merc 525 EFI's
 

I have a 2004 Fountain 47 Lightning (triple 525 efi) without smartcraft, and am going to be upgrading my chartplotter. What I would like to do is also add the Mercury Gateway NMEA 2000 so I can also monitor engine function, fuel burn rate etc. From what I understand this should be possible with standard Mercury plug and play parts, but am having a hard time finding what parts I will need. If anyone has already done this to their pre 2006 boat, and can shed some light on this, I would greatly appreciate it. Looking for parts lists, numbers, etc.

Thanks,

JR

I don't recall exactly what ECM's were used with the 04 525. But here's a link with similar setup that might help.

http://www.offshoreonly.com/forums/e...-question.html

See if ya can get a part # off an ECM, or shoot a pic of it and I'll look up the correct pieces.

As far as I know, all 525EFI's came with Mercury's 555 PCM.

Thanks,

JR

I think you will just need to run a blue merc can harness that has the terminators at each end of the harness. Plug one end into the eng where the terminator plug is and run the other to a j-box at the dash. From there just plug in the gateway to the j-box and to the garmin nmea 2k backbone. You will need to make a pig tail that will feed power, ground, and ignition power to the jbox. The gate way will not turn on otherwise. Since you said your engine is an 04 I am assuming it just has the older 10 pin harness running to the dash

Yes, my motors have the 10 pin connectors, but no Blue Can wire harness running up to the dash, just the 10 pin connectors on the motors.... Also, I think I need (1) 10 pin Blue Can wire harness with a Termination resistor on the motor end only, and (2) regular 10 pin Blue Can wire harness with no termination resistors feeding into a junction box and then the gateway plugs into the junction box as well. Or at least that is what I think I need.

I have an 05 35 fountain with 525's and I am adding this to mine this weekend if all parts are in. I ordered 2 20 ft merc blue cables with yellow termination resistors on the motor end, a jbox, the gateway device, and a nmea2000 starter kit. This will all be displayed into the garmin in the dash.
I did this on my 03 Baja with 496 and bought 1 blue cable with yellow termination resistor on motor, had a jbox and a yellow resistor on the jbox, merc gateway device and nmea2000 starter kit running to a lowrance hds7. works great. I just don't know if I will need the yellow termination on the jbox or not yet.

You will. You have to terminate both ends of the smartcraft truck line (and the NMEA 2000 backbone for that matter). For the smartcraft, if you are only running a line from the engine to a gateway (FYI early Mercmonitors would also convert Smartcraft to NMEA 2000) you can get a Smartcraft cable (blue cable) with a terminating resistor built into both ends. This will allow you go get rid of the junction box and just go straight from engine to gateway.

You will have to let me know if this works out and what part #'s u picked. I have an old Smartcraft book and it has a schematic that indicates you only need (1) of the blue cables to have a termination resistor on the motor end, and the other cable does not require it. This is for hooking up a smartcraft display and not a gateway unit though....

I will definitely let you know as I had problems figuring it out the first time I did it on my Baja and I really could not get any solid answers out of anyone except eric from EB marine in Henderson TN because he had just done it to a fountain. it seems as though your set up would work since you the termination is at the jbox, same way I am doing my except I am buying the 10 pin terminator and putting it on the jbox itself.

You will have to have two terminators in the system. One at the engine end of the harness and one at the dash end. You don't have to get the harness with the terminators in it, but it makes installation easier

Bajadan is also right about needing 2 terminators on the nmea2000 backbone

This is great. I am probably 2 months away from my install (due to weather)... I will start putting together my parts list and post so you guys can look it over.

Sounds like you've got it figured out correctly. I also agree you can skip the Jbox. Sorry for the late response, was away from the PC for a couple weeks.

How would you skip the Jbox with twin 525's? How else would you plug both motors into the gateway?

The Jbox is simply an "easy" connection hub for the Merc network cables. No matter what the setup, Merc, NMEA, ect, all CAN networks consists of two twisted wires, CAN-H & CAN-L, along with a 120ohm resistor between those wires at each end of the run. Your gateway requires a 12v power source, which I believe is provided from the NMEA network in this design.

I mistakenly thought Scagburner skipped the Jbox on his setup in the other thread. But after reading it again, he ended up using one. So sorry for that confusion. Easy plug-N-play includes the Merc cables and Jbox.

However "technically," you could skip the Jbox and connect directly to the CANbus pins on each ECU. Run those together then into the gateway with two resistors, and it will work just fine for a total investment of about $3.00. I use this setup daily for bench testing ECU's and gateways.

So do all (3) Blue cables from the motors to the J Box need to have termination resistors on both ends?

Did it. Nice because you get codes for alarm. Not cheap but nice having second opinion relative to analog gauges. Interfaced to Garmin chart plotter

completed this on my 05 fountain with 2 525's in it and had everything hooked up and running in about 15 minutes this weekend. You do not have to have termination resistors on both ends of the 3 cables. All you need is the termination resistor on the jbox itself.