Finally able to run my boat this weekend, ran great yesterday but today at about 30 mph it stuttered and died. No power anywhere, no unswitched accessories working, nothing. Haven't had chance to meter anyrhing, had to try and repair on water, have it towed in. I'm suspecting the main ground to engine broke inside the connection somehow, it's still attached to ground stud on motor. Any thoughts on where to begin? 2006 185 sport 4.3l. All fuses in block look good also, tried bypassing switch and wiring each battery in turn to leads, nothing.
Total electrical failure
- Thread starter JMG
- Start date
- May 14, 2008
- 3,538
- Boat Info
- 1988 390 EC
- Engines
- 454 Mercruiser Gassers
engine circuit breaker?
engine wiring harness connector?
engine wiring harness connector?
KevinC
Well-Known Member
Ground is a great place to start. Then work towards batteries and alternator. Sounds electrical so it should be able to isolate with a good multimeter.
-Kevin
-Kevin
Batteries appear good, 12.53 and 12.58v, respectively, which makes me think the alternator at least WAS working properly. I understand there have been issues with wires rubbing around the alternator and shorting out, will check in daylight. The engine ground is tightly secured to the screw/stud, tried unbolting it and it started to back out, winding ground with it, which is why I suspect the wire itself may have separated inside sheath, from the extreme angle it easily assumes. The circuit breaker is untripped as far as I can see. I have heard of a Cannon plug, not sure what that is, any info on that would be appreciated, as are any and all replies. The suddenness of the failure HAS to be a clue, and boy, what a long day this has been. Always an adventure.
Korkie
Active Member
- Feb 2, 2016
- 1,331
- Boat Info
- 2006 340 Sundancer, Garmin 7610, xHD 24 Radar, VV703, SeaStar Hydraulic Steer, Shadow Drive AP
- Engines
- Mercruiser 496 Mags
Bravo III Drives
Not familiar with your boat set up. First thought is - If switched accessories work but nothing that should power up with the ignition switch, maybe check there. Power to and from switch and then @ starter solenoid. Gonna be something simple, just gotta hunt it down.
- Mar 28, 2016
- 499
- Boat Info
- 1999 Sea Ray 290 Sundancer
2005 Sea Ray 320 Sundancer
2005 Sea Ray 340 Sundancer
- Engines
- Twins V-Drives
8.1 Mercruiser
There's a main 50amp breaker on the intake of that motor..... or Around there.... Check for volts on both sides, sometimes the breaker goes bad.... Its a big Red button that says 50 on it.....
Mike sandor
Active Member
- Jul 28, 2017
- 175
- Boat Info
- 2007 320 Sundancer
Twin 496. Bravo 3
2018 3500 Chevy, Loadmaster trailer
Raymarine Axiom, Quantum 2
- Engines
- 496 Mercruiser/Bravo III drives
Not sure if this will help but last year I went thru somethink similar. My batteries were low on charge, I used the emergency start to combine all batteries. The port engine started fine. The starboard engine started but died when I released the emergency start button. After trying a few things, I noticed that I had no audible alarm when flipping that motor start button. After a very frustrating week end, changing batteries, going thru every obvious fuse block, my son found this located on top of the engine. Blown fuse!! Problem solved!
Attachments
Bt Doctur
Well-Known Member
1 Locate the slave relay/solenoid and jump the two large studs, starter should spin. If nothing ,check battery cables both pos and negative.
2 using a jumper from the pos battery, touch the Yellow/red wire at the slave , starter should spin. If not check battery cables both pos and negative.
If the negative cable at the block spins the cable replace with a new cable to a different bolt
2 using a jumper from the pos battery, touch the Yellow/red wire at the slave , starter should spin. If not check battery cables both pos and negative.
If the negative cable at the block spins the cable replace with a new cable to a different bolt
Jimmy Buoy
Well-Known Member
- Dec 3, 2008
- 2,463
- Boat Info
- 2003 Cobalt 293
- Engines
- Twin Volvo-Penta 5.0 270hp & DuoProps
check on your DC breaker panel and see if the ignition circuit breaker has tripped.
Noticed this morning that the large orange cable connected to the alternator has rubbed bare and is contacting the alternator housing. Don't know if that's it but it's sure SOMETHING. Will look there first when I get time to mess with it.
Update-
Well, the frayed alternator wire definitely shorted out against the exhaust manifold, and upon studying the wiring diagrams I have available I am working on the theory that the short blew the 90 amp fuse attached to the starter. Pulled it this afternoon, it's bad. The positive battery lead attaches to the opposite side of the fusible link so that would explain the total loss of electrical power. I checked the alternator diode, still good, batteries still good, so it apparently did its job. Have another on the way, will update with any new info. Plan to repair alternator wire, or replace, and see what happens.
Well, the frayed alternator wire definitely shorted out against the exhaust manifold, and upon studying the wiring diagrams I have available I am working on the theory that the short blew the 90 amp fuse attached to the starter. Pulled it this afternoon, it's bad. The positive battery lead attaches to the opposite side of the fusible link so that would explain the total loss of electrical power. I checked the alternator diode, still good, batteries still good, so it apparently did its job. Have another on the way, will update with any new info. Plan to repair alternator wire, or replace, and see what happens.
KevinC
Well-Known Member
My theory was correct. 90 amp fusible link mounted to starter blew when alternator wire shorted out, killing all power to the electrical components. Replaced part, spliced new section of alternator wire, and rerouted cables to avoid hard contact. I think I'm good to go.
