2003 Johnson (Suzuki) and NMEA2000


I bought a boat last year with a 2003 Johnson 4-stroke 140 hp on it… which is essentially a Suzuki. Motor runs fine, and I would LIKE to set the boat up with a LowranceNet system and get the engine data displayed on Lowrance LMF-200/LMF-400 gauges and/or a HDS unit.

Do any of the engine/electronics gurus out there know whether this motor is putting out NMEA2000 data? Anybody have experience setting up such a system on a Johnson (Suzuki) that “old”?

I don’t want/need fuel flow data from the motor - I will be putting fuel flow/fuel level probes in the fuel system for that. Just the essentials… RPM, volts, oil pressure, alarms and checks, etc…

Lastly - any suggestions on who to take it to to get the work done?


2002 Duracraft 1548 - Mercury 25 2-stroke - and a paddle

Swamp rat,

I setup the the NMEA2000 network on my boat and added the Lowrance EP-20 (suzuki engine) modules for my 2007 DF140s. A picture of the module is below, the large connetor to the right plugs into the engine harness, and the small connector plugs into the trim sensor on the engine. If your engine has the connector, it will be located forward of the starter and above the black plastic enclosure on the port side of the engine, it will have a rubber plug in it. The trim connect is below in the front of the engine. If the engine does not have the plug, I am pretty sure it is not NMEA200 ready. If it does the plug, you will need to order the EP-20 module and connect it to your NMEA200 newtork, the EP20, I believe only comes with the blue (old) connectors, so if you network is new or your head unit is less than two years old, you will have the red connectors and will need a red to blue connector.

You mentioned you did not care about the fuel, that is probably the best feature and information supplied from the EP-20, at least on my engines it is very accurate, on a 70 gallon trip it is usually only off by a half gallon. I have a LCX28 HD and it has great fuel managment features.

Do not replace your analog guages with your engine alarms, they are very realieable, much more so than the NMEA200, plus you will not get the alarms on the Head unit or the LMF200 or 400, they will only display if you buy the Suzuki Simms gauges which are just branded LMF200 or LMF400 with slightly different software.

Anyway if your engine has the plug and you go to set it up and have any problems, I would be glad to help. The trim gauge setup if the most problematic, but once setup it works great.

Pursuitgang (RealTime)

2486 Triton w/twin Suzuki DF140s (RealTime)
1720 KeyWest 90 Johnson

pursuit is dead on accurate
its been a few years, but from what i remember, the fuel management doest measure fuel flowing through the hose, it calculates the amount of time the injectors were open, and turns that into a fuel usuage, which is very accurate.


I pulled the cowling off today to check - I found this connector, protected by a rubber cover.

I can’t tell if that is putting out NMEA2000 data, although I’ve gathered from here that some earlier Suzuki data was NMEA compliant before 2005…

Looking for the trim fitting, I saw this (iPhone pic… so it’s not the best) down sort of up front and to the left side of the block.

I’d be interested in knowing what data I might be able to pull to a Lowrance LMF-400 and LMF-200 gauge pair. I am going to be keeping at least the analog tachometer with the four warning indicators. But would love to get basic engine telemetry and fuel data run to LMF gauges. I’ve been hearing conflicting stories as to whether or not the 2003 Suzuki’s or “Johnsukis”) are putting out NMEA data.

Thanks for the continues help on this.

2002 Duracraft 1548 - Mercury 25 2-stroke - and a paddle

I seriously doubt that a 2003 Johnson (or even a suzuki) is equipped with NMEA 2k. Most engine OEM’s did not start adding this to their engines until around the 2006 model year.

The connector is going to be a small, round, 4 or 5 pin connector. And will be easily located.

If you can’t seem to find it, chances are your engine isn’t equipped with it.

Another option that you might consider (if you want to spend the $$) is a NMEA gateway. Lowrance might sell a module that you could use to convert some of the signals you’re looking for, into NMEA 2k and braodcast is over the network.


It is my understanding the EP-20 will work with all Suzuki DF model engines older engines may provide less information but should still provide the basic information. The engine itself does not provide the information in NMEA2000 format, that is the purpose of the EP-20, it converts the analog information from the engine and presents it to the network. The plug you show in your picture is where I have my EP-20 plugged in.

Pursuitgang (RealTime)

2486 Triton w/twin Suzuki DF140s (RealTime)
1720 KeyWest 90 Johnson

Good news! Soon I will have to get it going. I may keep the analog tach with the idiot lights as a back-up to I know I have a working warning system.

Thanks, folks

2004 Sea Pro SV1900 / 2003 Johnson 140 4 stroke

2002 Duracraft 1548 - Mercury 25 2-stroke -

I hope you have better luck with yours than I did with mine! I purchased the SMIS gauge and engine interface for my '06 200 Zuke for $350 a few years ago and wish I had saved my money for fuel, not to mention a new hole in my dash. The fuel flow meter was never accurate (even after walking through the recalibration sequence over the phone with a Brownspoint Marine technician). Also, it didn’t provide engine water temperature, oil pressure or any other engine diagnostics like I read it would, and when you linked it to the trim sender it bypassed the analog gauge. And it too had to be calibrated. When I sold the boat, the malfunctioning gauge was the only thing the new owners disliked about the boat.

I did learn a lesson though. NEVER, EVER drill a hole for any electronic device until you know for sure it works and that you like it!

For larger boats with higher horsepower engines, I can see their value but for low to mid-horsepower engines, I don’t see where there’s much savings.

Swamp rat, was you able to get the system running on your motor?? if how do you like the system? I have a 2005 johnzuki 140 and am looking into doing the same thing.

“Knee Deep”
2006 Pioneer 197SF
2005 Johnzuki 140