After 2 hours at anchor both engines refused to crank (not battery)

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Meagain

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Anyone experienced this with twin 2006 D4 installations? All things started well in the morning a slow motor in the harbour then anchor for couple hours. Then…. Go to start up, gauges light up, evc shows locked (all good), then nothing …. no cranking (dead). Seastart manged to get them going by applying 12v to the trigger wire on the starter solenoid so suggests it’s not the battery, but what else can do this to both engines ? Starter motors were changed while out of the water, so a fault on one engine would have me looking but chances of it happening on both ?
would appreciate any thoughts.
 
So it begins to sound like voltage, but having left the boat last night not starting I put keys in and she fired up! Then next time nothing. Connecting to shore power (with charger) both Start straight away, second, third etc. Disconnect and will start once but not a second time. So thinking it’s batteries swapped over domestic and crack batteries. First go starts, second nothing !!! So guessing that rules out batteries? Boat Galvanic isolators have been mentioned as slight corrosion is seen. Been all over engine / bay with multimeter ~12v seen.
confused !
 
A do voltage test when trying to start , I had the same whilst replacing the batteries I lifted a battery a soldered joint came out , so it was not batteries .
 
I’m thinking “poorly / corroded ground connection somewhere”.
If you trace around in the not-starting condition, you‘ll most likely see the voltage falling away to some very low value somewhere when trying to start.
Twin D4’s have separate HCU, PCU, fuel control units etc. so it has to be something fairly fundamental and common to both.
 
My VP d6 once refused to start. I think (???) it was because I had raised the outdrive right up. Once down it was fine.
 
Ok, silly question time. Located near the actuators on the boat hull are two sealed rectangular electrical units blue in colour with heat sink fins. They have fairly heavy (starter dia) cables running to them. 3 in number all positive 12v. What are they ?
im assuming some solid state isolator or something but cant find any reference when googling D4. Wondering if they could have a guilty part in this saga?
 
Meagain said:
Ok, silly question time. Located near the actuators on the boat hull are two sealed rectangular electrical units blue in colour with heat sink fins. They have fairly heavy (starter dia) cables running to them. 3 in number all positive 12v. What are they ?
im assuming some solid state isolator or something but cant find any reference when googling D4. Wondering if they could have a guilty part in this saga?
Click to expand...

Pictures would help … some sort of active corrosion protection system?
 
The fact you say the engines started every time with the shore power connected makes me think there’s a voltage related issue somewhere but probably not battery related.

The trigger feed to the starter sounds like it’s not getting enough power to excite the starter solenoid. On a simple key to starter set up relatively easy to chase but I’m guessing you’ve got some electronic wizardry which has to be placated before the engines are allowed to start, for instance you might have to acquire station control first (on a flybridge).

To I’d be looking at the low tension side rather than the high tension / main earth side.

A good engineer will be able to cure providing the fault can be replicated which it sounds like you can.
 
Our single engine setup is much smaller than yours, but we had a similar issue which turned out to be a faulty / intermittent battery isolator switch which was losing voltage. Do you have one or two of these for your twin engines?
Incidentally, before hitting the start button the voltage should be much higher than 12v. Others more expert would advise but our engine start battery is generally at least 12.7v.
 
It sounds to me that you have a bad earth somewhere. So when the voltage is on shore power all has plenty of oumph... When just on batteries the bad earth is not allowing a good currant flow once you turn the key.
 
Meagain said:
Anyone experienced this with twin 2006 D4 installations? All things started well in the morning a slow motor in the harbour then anchor for couple hours. Then…. Go to start up, gauges light up, evc shows locked (all good), then nothing …. no cranking (dead). Seastart manged to get them going by applying 12v to the trigger wire on the starter solenoid so suggests it’s not the battery, but what else can do this to both engines ? Starter motors were changed while out of the water, so a fault on one engine would have me looking but chances of it happening on both ?
would appreciate any thoughts.
Click to expand...
Check the connections around the ignition switch(s) as this is the source for the solonoids. Did the instruments light up?
 
Meagain said:
Ok, silly question time. Located near the actuators on the boat hull are two sealed rectangular electrical units blue in colour with heat sink fins. They have fairly heavy (starter dia) cables running to them. 3 in number all positive 12v. What are they ?
im assuming some solid state isolator or something but cant find any reference when googling D4. Wondering if they could have a guilty part in this saga?
Click to expand...

Something like this?

1681048772544.png
 
dunedin said:
Our single engine setup is much smaller than yours, but we had a similar issue which turned out to be a faulty / intermittent battery isolator switch which was losing voltage. Do you have one or two of these for your twin engines?
Incidentally, before hitting the start button the voltage should be much higher than 12v. Others more expert would advise but our engine start battery is generally at least 12.7v.
Click to expand...
multimeter reading are showing where tested ~12.7v. Did wonder about the isolator (there is 1 for both engines, 1 for service and 1 emergency to connect all together.
should add, using the emergency connector for both service and engine, made no difference.
 
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