Limp mode ? Neutral safety switch

[timf1981]

2017 DF25A tilt trim. Remote

Has anyone had issues with the neutral safety switch putting it into limp mode?
Is this possible?

Recently I believe my motor has been going into limp mode. Low rpm, sluggish.
Turn off ignition switch then it starts right up with full power until the next episode. It can happen at half or full throttle.
No error codes no red lights.

I have a scanner for it. Reads 147-150 water temp. And I have checked oil pressure a while ago. I can't find my notes but I believe 25-50 psi.

I have not had my timing light with me when the power drops to confirm a cylinder is not functional. I could have a bad coil on one of the three cylinders. But it starts right back up every time.

Anyone know which cylinder is dropped for limp mode?

I can also read the rpms on my Lowrance.
I rarely get above 5000 rpm.
Even if I raise the motor out of the water at high speed to activate the rev limiter. It does not go into what I think is limp mode.
What conditions can make it go into limp mode? Would a bad coil trigger a code.

Thanks...

[timf1981]

Here is the safety switch part number 37721-93J91-0000.
It is buried in the remote control.
Gas is fresh and fuel in engine has been flushed 4 times and filters cleaned with carb cleaner and air pressure.

[Moonlighter]

I haven't heard of a neutral throttle switch causing issues whilst the engine is already running at more than 3000rpm. I think that is what you are saying - you are going along at speed and the engine suddenly drops back to low revs?

3000rpm is the magic number for the NTS. If its dropping back to less than that, like a fast idle speed, then its not the NTS.

The usual symptoms of a bad NTS is that you start the engine, put it into gear, drive off but it wont exceed 3000rpm. Sometimes when that happens, bringing the engine back to neutral and jiggling the throttle may get it working again.

It sounds more likely that your engine is going into safe mode. The ecu will cut fuel supply to control engine revs, its not as simple as “which cylinder does it cut”.

Do you have a Suzuki tacho with the warning lights, or any other way on your boat to see the fault codes? The advanced model tiller arms have the 3 lights that show the codes, plus usually there are a series of corresponding beeps?

The alternative of course is to get it hooked up to the Suzuki diagnostic computer, the ecu usually will have recorded a fault code every time the engine has gone into guardian mode.

The other issue is voltage. If the engine isnt getting good voltage via both the main battery cables AND the white wire, then it can play up like that without any fault codes. So it cant hurt to undo those connections, clean them bright and shiny, and check the battery leads while you are there for any signs of corrosion internally too. Flex them around. They should be nice and flexible. If you have the equipment you could test their resistance. Check the fuse in the white wire too.

[timf1981]

I do have a suzki diagnostic computer. Maybe payed 150-200 dollars.
No codes.
The issue started on a trip. From the boat ramp out 15min it ran fine. Then it was as if someone yanked back on the throttle.
I was afraid to turn it off until I got to the campsite. I set up camp then went back to the motor. It ran fine. Normal acceleration. The rest of the trip it had issues. Turn it off and right back on , its fixed

When the issue pops up. It has no energy. Slow down to stand still and you give it some throttle and you notice it right away.

Does suzuki in the df25a have a limp mode and a safe mode?
I have driven the motor for 30 min before it acts up. And it has also done it one minute after a cold start. On the fourth of July it did it 4 times in the first 500 yds. We watched fireworks. The next day I drove it for 30 min. And no issues. I changed speeds , stopped accelerated hard and slow.

Now to the "WHITE WIRE" what wire are you talking about?
We talked back in May about the white wire for the cable hooking up the Lowrance to the motor. Yes, I hooked up all 4 wires including the white wire. It would not work without the white wire hooked up. And I mentioned earlier that I found two different color codes on the internet. And mine did not match either one.
I just went over your reply again. Which white wire has a fuse in it?

At the end of our trip. We did try unplugging the 4 wire cable from the engine. But my brother and I have a different memory on the results getting old.
I did clean up the connections this spring and even soldered the wires to a plug at the motor.

I think I mentioned this before. But I believe I saw the rpms on the Lowrance jump to over 7000 for a split second before the issue popped up and rpms crashed. It happened so quick. I am not 100%

I haven't tried it for a month but will be checking it today.
So I have the Lowrance and diagnostic computer to watch rpms. I also have a 12$ ebay rpm meter and my dads 50 year old rpm tac meter. And I know how to use a volt ohm meter. Use to do hvac work.
The motor does start and run with no battery attached

Tell me again what signal I should get from each wire at the motor end of the diagnostic cable and what colors they should hook up to on the motor.
Or is it the motor wires that supply voltage and signal and ground.

Let me know what additional info you need. I am going to go drive around in the boat for a while. Hopefully not hours until I learn something.

Thanks...

[timf1981]

Drove the boat for an hour on the 25th. No issues

[Moonlighter]

Is it possible that the engine is over-revving when the issue happens?

You mentioned seeing 7000rpm momentarily? If the prop loses grip on the water for a split second and the engine overrevs, that could cause it.

An over rev will cause the engine to instantly drop back to idle, if you then pull the throttle back to neutral and wait for sevral seconds it will reset and allow full rpm again. The overrev light comes on if I recall correctly.

If its not that, I have nothing more to add. Perhaps another forum member will chime in with some ideas.

[Murray]

Codes that will activate the fail-safe system.

https://www.suzukioutboardforum.com/...agnostic-codes

Scroll down to the two pdf files at the bottom and open them.

[timf1981]

When a event occurs. There is no beeping. None of the three lights on the engine come on. Waiting for a short time in idle does not correct the issue. Only a quick on-off of the switch brings it back to normal. Every time.
The scanner I have shows no codes.
There is a history of 11 over revs. Two of which I did intentionally by raising the motor slowly out of the water while driving down the lake to see if it would trigger an event. It did not.
I hear no over reving just before the motor loses power.
There is low power even at 2000-2500 rpms.
Hopefully I can drive it around more this weekend.

[timf1981]

Moonlighter.
What is the white wire you were mentioning?
It doesn't sound like neutral safety switch because it doesn't act like 3000 is a hard stop.. I am not sure if it can get up to 3000.
And it is sluggish between 2000-2500. Idles fine.
Thanks...