2009 DF115 Not getting full throttle sometimes..

[Kruzenvax]

As I posted here before (in "DF115 voltage related question" thread) I was too having NMEA interface/voltage related problems. While I was concentrating on the problem of loosing engine data reading from the interface at high RPM's/temp I believe that once or twice I might have had the same issue - not getting high RPM's straight after starting the motor.

The cause for "my" problem was high fluctuations of voltage from the (alternator/rectifier - whats is the right term here?) at high RPM's/temp - while the motor was working properly, the voltage fluctuations were very high compared to other Suzuki motors the dealer has tested. It seems to be fixed (at least I didn't notice any problem since my only trip after taking the boat back) by replacing the rectifier under warranty - been told the voltage is stable now in line with other motors.

What I am getting at: it seems to me that the voltage fluctuation that affects the NMEA interface may also happen when the motor is cranked. Perhaps that is also something to do with the rectifier (I don't know at which point the power is supplied to the SDS port)?

If that is the case, the root cause for all NMEA interface problems experienced by me/Moonlighter and others could be voltage fluctuations in some Suzuki's - while probably within the specs to operate the motor, probably too high for NMEA network/components , which as far as I can tell have lower tolerance for voltage fluctuations.

I will check if new rectifier provides the voltage stable enough for NMEA to operate at both ends of the range (cranking and high revs). Otherwise I may need to consider running some sort of voltage regulator for the boat electronics and power the NMEA engine interface as per Moonlighter's suggestion.

[Moonlighter]

Good to hear that you got your electrical issues sorted. They can be a real PITA!

I doubt if Suzuki here in Australia or Japan will do further investigation on the issue i had to discover the root cause, because it doesn't affect current A series engines, and secondly, they have a simple solution anyway.

But you may well have something in what you say about the regulator. It does seem to be a power issue of some sort at the root cause. On a few occasions i got a low voltage warning on my Lowrance display, which we now believe to have emanated from the ECU. I will watch my engine voltage readings next time I go out to see what they are doing.

I have had the boat on the water 3 or 4 more times, and no recurrence of the problem, so the solution is looking good! Touch wood!

[Kruzenvax]

Two eye-openers fro me in your previous post, Moonlighter:

1) That NMEA interface is powered from the SDS port , not from the network (thought it may be the case though)

2) That NMEA interface can "talk back" to ECU (this one I could have never imagined).

If voltage fluctuations from rectifier is the problem (and I believe it is), the workaround from Suzuki Aus can fix low voltage when cranking problem (yours) and perhaps mine (interface looses reading when voltage is above NMEA specs, but how about sending those sparks to all the remaining boat electronics? Batteries?

[kutlingen]

Really nice info here. I fabbed an interface adapter this summer, and all seemed to work fine when tested. Once on the water, I had the exact same problem as described in this thread. I unplugged the adapter and all wass fine again. Assumed that i ****ed up the adapter, and havent used it since.
So the solution is to just cut the red wire at the plug, and connect it directly to 12 volts? Could it be at the starter motor, or does it have to be on the aux battery?
Thanks for the info, i sure appreciate it!
Bjørn

[Moonlighter]

Yes, just provide 12v direct to the red wire in the interface cable.

You can achieve that however you like. But I would suggest not to connect it to the positive terminal on the starter motor, just because that is a source of voltage spikes and drops when engine is cranked.

Direct to the start or house battery or an adjacent battery master switch would be preferred. It is a good idea to be able to turn power to the interface cable off, rather than have it powered all the time, so some switched source would be the best option.

I actually cut the wire in the adapter cable that connects to the red wire (peeled back the heat shrink and the wire cover and cut it a few inches behind the plug) and joined that to a new section of wire that is connected to the positive busbar behind my dashboard. This way, the interface cable itself remains untouched and in perfect condition.

I also disconnected the power wire in the adapter plug back at the engine where it plugs into the SDS port, thus removing that source of power to the power wire in the adapter cable.

I dont think it will matter which battery the interface cable gets power from. In my case, i have a twin battery setup, one starting battery and one house battery, with a BEP twin battery VSR setup, and my house battery supplies power to the positive busbar behind the dash for all electronics etc. So that was the convenient solution for me because my interface cable lives up behind the dashboard too.

And the solution works!

Cheers

Grant

[Moonlighter]

Two eye-openers fro me in your previous post, Moonlighter:

1) That NMEA interface is powered from the SDS port , not from the network (thought it may be the case though)

2) That NMEA interface can "talk back" to ECU (this one I could have never imagined).

If voltage fluctuations from rectifier is the problem (and I believe it is), the workaround from Suzuki Aus can fix low voltage when cranking problem (yours) and perhaps mine (interface looses reading when voltage is above NMEA specs, but how about sending those sparks to all the remaining boat electronics? Batteries?

In my case any voltage fluctuations back to the boat electronics will be minimized because i run a separate house battery. Perhaps. I haven't noticed any other issues with electronics and think i would have by now if it was going to happen. Had my boat with this setup for 3.5 years.

I think it may be worth you trying this "fix" and see if it helps with your other problems as well. It is such a simple and inexpensive thing to do, and as far as I can see, no downside risks from doing it. So, IMO, it would be well worth giving it a try to see if it helps.

As far as it "talking back" to the ecu, i am not sure exactly what is happening, it may be that the ecu simply detects the low voltage situation in what is now sees as a sensor - and responds the same as it would to any other such situation. I did see a couple of "low voltage" warnings pop up on my Lowrance HDS screen when restarting the engine after this problem occurred, and i now believe that they weren't from the Lowrance detecting low voltage, i think they were messages from the Suzuki ecu.

[kutlingen]

Great. My power setup is exatly like yours, with same componets, so i just do it like you did, as we know this works.
Thanks for sharing the info.
Bjørn

[Moonlighter]

Great. My power setup is exatly like yours, with same componets, so i just do it like you did, as we know this works.
Thanks for sharing the info.
Bjørn

Happy to be able to offer any help to our friends in colder climates!

Cheers from the Australian division of the Suzuki outboard forum!!

[kutlingen]

Colder climate? Dont know what you are on about. Temperature this morning was -6 degrees :-) And windy too.....
I would love to go to Australia for the entire winter!
Bjørn

[Moonlighter]

Hi Bjorn

Currently 21.4C here in Cleveland, Queensland at 10.20pm. Very pleasantly cool for an Australian summer's evening! Expecting 20 - 30 this weekend, storms and 25-30 knots of northerly wind, so won't be getting the boat on the water unfortunately.

Winter around here, where we are on the coast, is typically our best boating weather with light wind and sunny days temps 9 min 23 max. Hard to take!

Cheers

Grant

[Kari Vainola]

Moonlighter:any pics about the wiringjob?

[Moonlighter]

No pics. It is pretty straightforward as described earlier in this thread.

Is there something you are not sure about?

I can also report that I've done several more trips without any recurrence of the problem so am prepared to call it solved.

[Jjade268]

03 suzuki same problem

I think I have the same problem she turns on with no problem run good as long as it is under 3k I do about four knots give or take .but once I go any higher she starts to bog and spit was thinking it's the fuel pump but not sure one that I read this .dont know if I should try this .and ps my fish finder flashes low footage at times but not all the time . I run two bats and both fully charged and in great conditions .i need help lol thanks to all

[Moonlighter]

Hi Jade

If you have the NMEA2000 engine interface and the problem you have is the same as described in this thread, then this could well be your problem.

The solution is described quite clearly earlier in the thread so I am not going to repeat it again. See my posts numbers 13 and 20 for details of the fix and how I did it.

I can definitely confirm that yes, the problem is now solved, it has not recurred, so the solution detailed in this thread is a definite solution for this specific problem.

If you don't have a NMEA2000 network on your boat, then of course this will not be the solution and you must have another problem.

Another thing that could cause similar symptoms is the engine hitting the rev limiter and it could do this at around 3000rpm if the neutral safety switch on the engine is faulty or not positioned correctly.

[Jjade268]

Thanks

Will ck it today I hope that is it thanks again .were do I find the interface number thanks