Df 300

[dragline]

Hi everyone.
I recently purchased a boat with twin 2007 df300 motors on her. This is my first set of suzukis that I have owned I have always had Yamahas prior to this.
So far I am very impressed with the engines with one exception, the starboard engine is using 60% more fuel than the port engine according to the engine gages.
Has anyone encountered this problem before and what should I tell the mechanic to look for to correct this problem

[rustynutzz]

The experts should chime in soon but I would check gauge calibration first. Other than the gauges have you confirmed fuel consumption with a flow meter?

[Solarman]

twin df300's, fuel rate questions

The key words here, you said yourself... ”According to the gauges”. do you have separate tanks for both motors (if separate, do you fill them with different amounts at the pump), or operate from one tank? Might buy a couple small tanks if only one, fill them equally, then refill after running for a period, or see if they run out at same time. Am not sure if the gauges are reading accurately? Maybe gauges weren't setup correctly in beginning?
Moonlighter (Grant) may be able to suggest other ways to check gauges, or consumption?
Good luck.

[Moonlighter]

I agree with the earlier comments. It is most unlikely for one engine to ACTUALLY be using that much more fuel.

I would immediately suspect that the interface for that engine has not been configured correctly. Perhaps, the interface failed and was replaced, but is running the wrong software version.

You will have to do some diagnosis for us. That will mean learning a bit about the Suzuki engine monitoring system, SMIS gauges and the interfaces.

First, I am assuming that you have the Suzuki SMIS digital gauges. That being the case, here is a quick explaination of how the system works. It is totally different to the normal analogue gauges and nothing like the Yamaha system.

1. The system is built on a NMEA2000 network. This simply consists of a set of T shaped connectors that each device is connect to, all,of which are linked together, a switched power source, and a terminating resistor at each end.

2. Each Suzuki engine is connected to the network via an "engine interface cable" that plugs into a T piece. That cable has in-built software that converts the data from the engines ECU to NMEA2000 so it can be displayed on any network display.

There are some issues with wrong fuel flow data when pre-2010 engines are connected to new interface cables running the latest software. Also, each cable has to be configured -basically, this just means to set it up so it knows what year and hp engine it is talking to. Easy to do.

3. The data from each engine can be displayed on any NMEA 2000 capable multi-function screen, such as a sounder or GPS screen. It can also be displayed on a dedicated engine data display, such as a Suzuki SMIS gauge, a Lowrance LMF400 gauge (which is actually identical in nearly every aspect to the SMIS gauge), or a Garmin GMI-20 display.

4. Engine data will only appear on the gauges when (a) the gauges are powered on, and (b) both engine keys are turned to the on position.

5. Every time When you refuel the boat, you need to tell the system that you have done that, so it knows how much fuel it then has in the tanks. 2 options when you are doing this: one, is when you fill the tanks to full, you reset the fuel level to full. Option 2 is to partially fill the tanks, and in that case you input the amount of fuel added to each tank.

Questions:

In your boats case, as mentioned previously, I am assuming that you have a couple of SMIS gauges. correct?

If so, the gauges will likely activate when one of your engines key is turned to the on position, correct? That is the normal situation, and it means that the network is getting powered via a connection to the wiring harness of one engine.

It might be worth downloading a SMIS gauge owners manual because it shows you how to operate these gauges and to set them up how you prefer. It will also make what I am saying next easier to understand.

What we need you do do is to turn on the network and turn both engine keys to "on". Engines don't need to be running, just that they keys need to be on.

Then, on any gauge, press the menu key and scroll down to find the network menu, open, then find the device list menu, and open it. You will then see a list of devices that are active on the NMEA2000 network. With both engines keys turned on, you should see 2 Suzukis listed there. They will typically have been labelled as port and starboard by the person who set the network up.

Scroll to one of them, and select it, and check the configuration. It should give a number of details on that screen, including a software version, engine hp, year etc.

Make a note if these details, do the same for the second engine, and report back, and we can take it from there.

[dragline]

instruments

Thanks guys, the engines are connected to the garmin 7215 gps X2 and also to 3 smis guages in the console, they all seem to display the same info and result.
I will get the info that you asked for and repost ASAP

[dragline]

instrument update

So after some investigation the guages are the LMF 400 type.