The " It suddenly stopped running" story again

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
Got to hand it to the engineers on this one. 3 year old boat with the new emission package, cats, etc. operated very well the day before, the next day it was a no start. no fuel delivery, no fuel pump pre-prime sound. Everything else worked.
All engine breakers checked, all ENGINE fuses checked, engine relays swapped.

This lone fuse was sitting directly on top of the battery along with it`s spare replacement fuse in a plastic bag on the wire.
Originally thought it to be the bilge pump feed but following the wires it led up to the main wire harness. Fuse rating was 5 amps so it couldn`t be for the bilge pump anyway.

Removing the cover, it had blown the fuse from what I would describe as simply battery vapor corrosion and thats why it blew.The spare fuse also had heavy corrosion on it also and it was in plastic. Had a factory tag on the engine side as "clean power" ,guess the factory decided a direct battery connection for the computer was best.
Replaced with a jumper and boat now ran.

My fix was to cut away the fuse that was laying on the battery, direct connect the leads to the battery and install a new fuse holder on top of the motor near the other ones on the motor
Local marina wanted to try replacing the fuel pump first, an expensive guess. Guess nobody tries to fix anything anymore.
Just keep throwing parts at it so see what sticks.
Migh have to save and blowup the pic to see it better.

So ,if you have fuses laying on top of your battery, move them to a safer location before you get stranded.
DSCN3463_zps0e4txwr6.jpg
 
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Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
Never thought to get a serial number ,a newer 2012 ish MPI 5.7 ? 5.0? Seemed to power up the computer only for fuel priming,spark ,etc. etc. All other switches, breakers, etc had normal power conditions.
All the feeds were tagged for what they do, fuel pump relay, trim relay, starting relay, OBD,.
Only thing missing was the power for the ECM. The feed was tagged as " clean power" and went to the module.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
That reminds me of a fridge problem I had. It stopped cooling on the fridge side but the freezer side worked. A repair guy came out and said the main board was the problem because the fan was not getting voltage. I do electronics so looked into it myself. Turned out if the fan doesn't turn when given voltage the computer won't supply it. Ended up being a $10 fan and I did it all myself.
 
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GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Do you know if the engine had digital shift components with smartcraft that use fancy ignition keys something like these, http://greatlakesskipper.com/baylin...hrottle-shift-engine-boat-ignition-key-switch

Clean power started with the use of needing direct power up to the helm to power up the Mercruiser digital shift command module mounted under the helm area. DIGITAL THROTTLE AND SHIFT KITS

It sounds like the new cars where the battery is always powering the computer so things like key-less start and remote start work.

More and more things to drain a boat battery, unless the boat is used often.
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
I`ll be passing the boat this week, will get the eng number and check it for DTS
 
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