Slightly Scary D4-260 PCU Failure

SC35

SC35

Well-Known Member
Joined
13 Jul 2021
Messages
3,217
Visit site
What you want when docking:
"Everything to work as expected"

What you don't want when docking:
- A piercing and continuous alarm to go off, making communication with Mrs SC35 almost impossible.
- I attempt to lip-read ... it looks like "What the sheep is going on".
- The engine is still running, but a bunch of EVC unhappy alerts are scrolling away on the Port engine.
- I attempt to engage gear on the Port Engine ... nothing happens.
- I decide to shut down the Port Engine ... nothing happens!!!
- Fortunately it's the upper end of a Force 1, so crabbing into the berth with the Starboard Engine, a lot of bow thruster, and a roving fender isn't too difficult.
- The alarm finally stops and the Port Engine gives up the ghost.
- We tie up, and I open the engine bay doors to find a smell of electrical burning.
- OMG
- Kill the main battery switches, and wait. Nothing seems to actually be on fire.
- Pour myself a drink and wait a little longer.
- Try sniffing things, and the PCU unit smells distinctly crispy. The upper right hand side corner of it is hot, unlike the PCU on the Starboard side, which is cold.
- Turning things back on, the Port Engine is as dead as a dodo. Nothing on the gauges.

Had dinner, and went back later.
Swapped across the PCU from the Starboard Engine, and the Port Engine fired up immediately, so at least I know it's the PCU.

The scary bit is ... what would have happened if the PCU had failed a few seconds later with the engine in gear?
Even the key didn't stop the engine.
The resulting video could have been a "boating fail 2022".

New PCU only £2300 :cry::cry::cry:

image0.jpeg
 
Sounds grim. The worst case scenario is the stuff of nightmares! Glad you only needed to experience it in your head. Time for a few more drinks...
 
Not a good scenario.

I guess if it was stuck in gear and wouldn't switch off at the key, I'd try the emergency stop button on the engine - have a look in the manual - its always worth knowing where this is for your scenario - on the d4 its located on top of the engine above the air filter

I did have a scenario a few years ago (on a sealine s34) where the bow thruster became stuck on, and wouldn't switch off, that required some frantic digging in a locker to locate the bow thruster battery circuit breaker to get back under control.
 
Last edited:
Is there a “emergency “cut off somewhere in the ER , perhaps located on the engine or some sort of ECU black box ?


87DF5D36-D116-4F6C-A263-A237FBC6F384.jpeg
Its actually kinda spring loaded to trigger shut just needs a twist and it snaps shut killing the motors .

When working in the ER I sometimes catch it unknowingly and its “ off “ . I realise because at the dash when I next turn the key its dead as a dodo nothing. So I go and twist and pull it re cock it ,and the box lights up etc .
 
Portofino said:
Is there a “emergency “cut off somewhere in the ER , perhaps located on the engine or some sort of ECU black box ?



Its actually kinda spring loaded to trigger shut just needs a twist and it snaps shut killing the motors .

When working in the ER I sometimes catch it unknowingly and its “ off “ . I realise because at the dash when I next turn the key its dead as a dodo nothing. So I go and twist and pull it re cock it ,and the box lights up etc .
Click to expand...

Could you turn off the fuel spigot at the tank?
Click to expand...

see post #6 there is an emergency stop button on the d4 just above the air filters.
 
Bouba said:
Could you turn off the fuel spigot at the tank?
Click to expand...

That would take ages before the filters drained.

There is an emergency shutoff on the engine, but pulling the hatch, diving into the engine bay with running engines and pressing it before hitting something in the Marina probably not possible.
 
Last edited:
SC35 said:
That would take ages before the filters drained.

There is a shutoff on the engine, but pulling the hatch, diving into the engine bay with running engines and pressing it before hitting something in the Marina probably not possible.
Click to expand...
Would a broom handle or boat hook be any use to tap it ?
Is there a facility ( to finally dock ) of a few guys from the marina with ribs to back you in safely with zero power , ie no motors at all ?

You do see it now and again in busy marinas ……some sort of power failure at attempting berthing and the ensuring calamity.
 
Portofino said:
Would a broom handle or boat hook be any use to tap it ?
Is there a facility ( to finally dock ) of a few guys from the marina with ribs to back you in safely with zero power , ie no motors at all ?

You do see it now and again in busy marinas ……some sort of power failure at attempting berthing and the ensuring calamity.
Click to expand...

It’s a small marina, there is nothing like that. The shutoff button requires a firm press, not just a tap.
 
At least you know exactly what the problem is and its merely :eek: a minor case of finding the money.
A quick ring round to find out who will supply the unit at the best price (Keyparts ? ) and sounds like a 1/2 hour DIY installation if no set up complications.
Assuming on the shelf or even if ordering from Belgium on your doorstep in 48 hours. In a hurry drive down and collect.
Then off boating again enjoying this great weather.
On the up side theres no spending time and money tracking down somebody prepared to even try and diagnose the problem and then randomly replacing bits in an expensive elimination game.
 
Bouba said:
If you are in the marina and stuck in drive…then leaving the helm is probably not the best idea
Click to expand...

If you are in the marina and stuck in drive…then leaving MrsSC35 at the helm is also probably not the best idea.
 
You must log in or register to reply here.

Other threads that may be of interest

D
Stern drive KAD32p - water dripping, any tips?
Replies
4
Views
246
James jameson
J

Share this page

Top