Boat has no power

[jvianco]

Boat had been running perfectly until I had two dead batteries in the boat, so I replaced them with new batteries of the exact same kind.  I put the boat in and it fired up and after about 3 seconds it shut itself off.  The boat had no power afterwards... No gauges, no fuel pump priming, absolutely nothing. After a week of intermittent troubleshooting, I disconnected the batteries and reconnected one.  Power was restored, but upon starting, it shut down immediately again.  No I have no power again, and disconnecting the battery doesn't seem to reset it this time.  I took both batteries last night and had them tested, and was told they are both good.  I removed the battery switch and went straight to one battery, nothing.  I tested the voltage at the starter, and it's reading just over 12 volts.  I checked the 50 amp circuit breaker, and it doesn't seem to be tripped, and voltage is over 12 volts on each terminal on the back of it.  I can't get it into the shop for another week.  Anyone run into this issue before or have any suggestions on what to try next?

The boat is a 2002 Wakesetter VLX with the 325 Monsoon engine.

Edited August 6, 2022 by jvianco
Added boat details

[wakesonthesnake]

Check all the grounds.

[jvianco]

13 minutes ago, wakesonthesnake said:

Check all the grounds.

I've checked all of the grounds that I can find.  Any documentation on where they are all located?

[wakesonthesnake]

Sorry I do not. Have not owned that model.  

[Bozboat]

No power? 
meaning none, no electricity past the battery?  When do you get the 12v readings referenced above before or after a no power engine stall?
 

Edited August 6, 2022 by Bozboat

[jvianco]

1 hour ago, Bozboat said:

No power? 
meaning none, no electricity past the battery?  When do you get the 12v readings referenced above before or after a no power engine stall?
 

The readings are after the no power.  Nothing on the dash works.  No gauges, no rocker switches, nothing when you turn the key either direction.  I cannot figure out what is causing this, and the only thing I did was replace the batteries from the last time it ran fine.  I've traced all of my battery cables to ensure that none of them got crossed during the swap, and they all look good.

[Bozboat]

9 minutes ago, jvianco said:

The readings are after the no power.  Nothing on the dash works.  No gauges, no rocker switches, nothing when you turn the key either direction.  I cannot figure out what is causing this, and the only thing I did was replace the batteries from the last time it ran fine.  I've traced all of my battery cables to ensure that none of them got crossed during the swap, and they all look good.

Is there a ground wire from the battery to the ground bar under the dash?

I would hunt around for a loose ground, IDR if I have a smaller red wire to the battery selector switch that powers the dash, but would look for that as well, something got disconnected that powers the dash and ignition switch

Edited August 6, 2022 by Bozboat

[jvianco]

12 minutes ago, Bozboat said:

Is there a ground wire from the battery to the ground bar under the dash?

I would hunt around for a loose ground, IDR if I have a smaller red wire to the battery selector switch that powers the dash, but would look for that as well, something got disconnected that powers the dash and ignition switch

That only happens after it starts and shuts itself down.

[Bozboat]

20 minutes ago, jvianco said:

That only happens after it starts and shuts itself down.

I’m not a boat mechanic, just a common sense type, something is getting disconnected and reconnected. A loose ground wire to the ignition switch might be worth checking, iirc the ignition switch grounds to the bus bar under the dash and the bus bar grounds to a battery.  Most of my boat issues are something minor like that. You mentioned that it worked fine before the battery swap and now doesn’t, that is a big clue. 

[jvianco]

I'm not a boat mechanic either, but I have a hard time believing it is the ignition switch when typically all other things on the dash, stereo, bilge pump, fan, ballast pumps, horn, etc all work without a key in the switch, but when this happens, everything stops working, key or no key. To me, it's almost as if the boat is tripping something much like it does when it overheats, but this only gets reset by disconnecting the batteries, and the boat doesn't run long enough to be overheating.

[justgary]

You'll probably need to grab a meter or test lamp the next time it happens and start figuring out where you do and don't have power.

I would start by violently shaking the battery cables to find the broken terminal.  Heck, you don't even need the meter for that. Just turn the blower on and start shaking wires.

[drh]

2 questions: What happens when you jump the 12v at the starter to the solenoid? What is the voltage at the starter or output side of the circuit breaker when the key is turned to "start"?

[jvianco]

Just to close this thread out, I have no idea what the issue was.  I tried to start the boat today, and it started up and ran perfectly fine.  The only changes I made between tries was pulling both batteries out and took them to be tested and reinstalled them, I tracked down the main ground going to the engine, and it was clean and secure, I swapped the impeller, and I pulled two of the relays out and checked/reinstalled them.  I hate not knowing what resolved it, but the boat runs and we can get back out and enjoy the water again!

[drh]

Very high possibility it could have been a tiny amount of corrosion on your battery cable terminals. An almost invisible amount of corrosion on my positive terminal caused my boat to go totally dead when trying to restart on the water one morning...even after starting up fine just a few minutes earlier. Still might be a good idea to hit them with a wire brush.

That's why I asked what the voltage read at the starter when trying to start. You can show good voltage with no load but as soon as you put a load on it, it will drop to nearly 0 due to a bad connection.

Anyway glad it's fixed!

Edited August 9, 2022 by drh