Df40 strange and dangerous problem

[Quarktop]

Hi all, I am new in this forum and I kindly ask you To help me solve a problem that left me at sea without engine:
I have a df40 2004 that has worked always well.
I was hanging around and for no reason engine stopped.
No diagnostic, no sound.
I tried to restart it but there was no cranking (the starting engine didn't work). After some minutes and many tries starting engine returned working and engine start well.
After 5 minutes it happened again in the same way: starting engine did not work, waited some minutes and after all well.
No diagnostic at all. In my opinion this is not a behavior of protection (it would be really unsafe to stop engine).
After some trouble I was capable to come back to the port and engine apparently is now working well (I checked it inside port because outside there is great wind (I am in Sardinia). Local mechanics have no idea.
I am really worried of this behavior. Can someone help me? Any help will be appreciated.

[Moonlighter]

Likely to be electrical.

Battery is low/failing, or a bad connection, corroded battery cable, poor or corroded connections to battery, or something similar in the wiring from battery to the engine or if you have a master battery with, in the switch.

What you described could even be if the battery was low, the engine cut out due to low voltage, the battery recovered after a while so it went agaiIn.

Check those electrical things, and let us know how you go. It will almost certainly be something like that.

[Quarktop]

Hi moonlighter, thanks you for your replay. I agree with you. Electrical problem was also my first choice.
I checked battery and before my first exit on the sea I recharged it. Voltage meter measure 13v and when starting engine recovers from failure it starts fast and without hesitation. It doesn't seem a problem of low battery.
I checked all cables and they seem ok.
I have a switch between battery and engine and to be sure I will replace it in next day (I bought it and I am waiting to receive it).
Forthermore I am not sure that this switch is responsible of the issue because if engine is running and you switch off the battery, engine normally should still run. So probably, the engine stop doesnt depend on switch (on the countrary the switch can be the responsible of failed starting engine). Which is your opinion about?
I have gps and sonar powered by the same switch and they were on during engine failure.
Now sea is rought and for safety reason I cannot execute any test (unfortunately in the port engine works fine.


A question from a none expert: Since the issue happened at rough sea and at flat sea inside port all is fine, couldn't it depend on water coming inside the exhausted fumes hole ?

[artdf175]

sounds like the "white wire" problem
what I don't know with dual motor set up is whether there are two sets of white wires - one for each engine
need to check for a connection that looks good from the outside but the wires are corroded off inside the connection..
in my boat this white wire feeds the dash/instrument panel and then back to the ignition switch .. so when the connection failed.. I lost power to everything and at first, it was intermittent, just as you have experienced.
fortunately, when it finally completely failed, I was in the driveway.

I would suggest to start looking at the wiring near the battery and battery switch and connections that can be exposed.
I recently discovered testing this white wire for voltage is not the best test.
you have to be an electrical engineer to read the wiring schematic but there is feedback to this wire through the ECM..

the other possibility is the neutral switch.
if you can swap power leads from one engine ignition switch to the other and then the the wire that feeds back to the engine(s)
the first will tell you if it is a white wire problem the 2nd if it is a neutral switch and/or bad ignition sweitch

good luck and let us know what you discover
Art......

[Moonlighter]

Hi moonlighter, thanks you for your replay. I agree with you. Electrical problem was also my first choice.
I checked battery and before my first exit on the sea I recharged it. Voltage meter measure 13v and when starting engine recovers from failure it starts fast and without hesitation. It doesn't seem a problem of low battery.
I checked all cables and they seem ok.
I have a switch between battery and engine and to be sure I will replace it in next day (I bought it and I am waiting to receive it).
Forthermore I am not sure that this switch is responsible of the issue because if engine is running and you switch off the battery, engine normally should still run. So probably, the engine stop doesnt depend on switch (on the countrary the switch can be the responsible of failed starting engine). Which is your opinion about?
I have gps and sonar powered by the same switch and they were on during engine failure.
Now sea is rought and for safety reason I cannot execute any test (unfortunately in the port engine works fine.


A question from a none expert: Since the issue happened at rough sea and at flat sea inside port all is fine, couldn't it depend on water coming inside the exhausted fumes hole ?

I don't think it is likely to be related to water entering the exhaust. If that happened, the engine would hydro-lock and not start again, ever!

I think the connection to rough weather conditions would be more likely to be a wire moving and therefore losing contact.

When you checked the battery connections, did you undo them, clean with wire brush, reconnect and tighten? Did you check the cables to ensure there is no internal corrosion - if you flex them around they should be smooth, no "crunchy" feelings. That is what is required.

Also, suggest that you take the battery out of the boat and have it tested to make sure it is good under load.

Also as Art said, look for a white wire connecting to the battery + for each engine, and trace it to the problem engine and also to the dash. This is a critically important wire as it supplies power to the ECU. Find all connectors on this wire, unplug them, inspect them for corrosion, clean and reconnect. Also check the wire itself in case it is internally corroded or has rubbed through somewhere.

[redlowrey]

Leave the engine running with the cowling off, and jiggle the wiring loom around the engine right up to your console, you might have a broken or loose voltage supply wire, be careful with the cowling off.

[redlowrey]

I forgot to add, when ever you check a battery do it under load. Hook a volt meter up to your battery and check the voltage drop as it cranks over, a good battery would not drop below ten volts.

[Quarktop]

Thanks all for support.
I will follow all suggestions
Only one question: Which is the mean of "white wire"? It mean neutral wire?
Sorry but I am Italian and my English is poor.
Tomorrow I will replace breaker and I will check all wires.
I will inform you about results.

[Solarman]

you may have a bad connection before/at/in ignition switch, if motor shuts off when rough sea, and starter motor not working, unless in port where calm.

But the waiting for time, before it will start? Possibly a two item problem? Fuel causing motor to shut down, and neutral safety switch affecting start motor?
Maybe kill switch, and neutral safety switch at controls taking most beating, getting loose?

Would white (color) wire affect starter motor, and shut motor off in rough seas?

[Quarktop]

Hi Solarman, ignition switch is a good candidate.
But why after 5-10 minutes starting motor return works well?
About neutral switch I shake it several time pending failure without any results.
This behavior seems as protection of ecs but in service manual always ecs protection is described as limitation at 3000 rpm or less. Never ecs protection stop to the engine. Did you can confirm this?
Tomorrow I will substitute kill switch and I dismount the ignition switch to check it.
Impossible go out the port because of strong wind.

[artdf175]

"Would white wire effect starter and shot engine off in rough seas"
YES
Any disruption in the white wire shuts the engine down-immediately
It happened to me
I think the 'waiting' time is just coincidental
And you are correct the engine rpm is limited if it senses a problem but does not kill it

[Quarktop]

Hi all,
Yesterday I changed the kill switch and the problem seem solved.
I run on rough sea for four hours without any problem.
Possible explication of what is happen: the kill switch was defective and impedance was not low. Current passing on it increase temperature and this open contacts inside it. After some minutes temperature decrease and contacts return close. Kill switch works as thermostat.
I want to tanks all people that support me and put me on the right way.