New electrical issue

[fsts2k]

The last few weeks I have noticed the voltage meter showing 10.5 volts but the boat was starting and running fine. Today when I started the boat I put in the code and pressed start, then pressed it again to turn on ignition, the boat went dead. I typed in the code again, first light came on, pressed start to get ignition, died again. Third time it fired but the perfect pass cycled on and off 3 times before just staying on. Generally seems like it is low voltage.

I took a voltage reading at the battery and it was 12 volts. This has just started, once I got the engine started it was fine. One time the electrical **** off, engine died, started it up again and it was fine. Does this indicate the battery might be going? Seems odd why I am getting 12 volts but the boat is showing 10.5. I checked the alternator output and it was getting 13+ volts.

Thoughts?

boat is 2002 Ski Nautique w/ gt40 engine

[fsts2k]

I should mention I have it on a trickle charger all day, will let it sit all night and check again in morning

[bturner]

Like most of these issues the more information you have the better equipped you are in making suggestions or trying to remotely troubleshoot. I'd like to think I'm fairly good at these types of issues but had one stump me this spring on my new Waverunner a couple weeks back. Anyway.....

In this case the first questions I would have is how old is the battery and how long had it been sitting before having this issue? If this is happening while the boat is being used regularly, I'd say you either have bad connections or the battery is in a downward decline and should be replaced.

The resting voltage of a good battery is somewhere between 12.4 and 12.9 volts. If you've been out skiing the boat all day without hours of party time at the sandbar with the stereo on, I would expect the battery to be at or slightly above those voltages when you got back to the dock. Same for the next morning. If you're not seeing this, IMO you should be doing a nut and bolt at the battery while inspecting and cleaning everything along the way. If this brings no joy the next stop would be at the local auto parts store with the battery for a load test. If the battery is more than 5 years old, I'd consider replacement regardless.

The issue I ran into is a classic for not trusting static voltage for battery health. I purchased a new 2023 model Waverunner last December. The boat sat for 2 winters before being put into service. Little did I know that the batteries are shipped disconnected with the skis. This means my new Waverunner came with a 2 YO battery that had not been charged until it was prepped for delivery. When launched and started using it I noticed it started slow but didn't pay much attention. After sitting for about 2 weeks the battery was dead and showing 10.9 volts. I charged the battery, the voltage after charging was ~12.4 volts, wonderful. Threw the battery back in the ski and dropped it in the water. When I went to start it, it made a couple clicks and refused to start. The dash showed a voltage of 10.9 volts. This is a classic indication of a bad cell. Looks fine at rest and falls apart under load. Threw a new AGM battery in it and haven't had any issues since (insert sound of be knocking on my wood workbench).

In your case, I'm thinking your battery is just getting tired.

[jpwhit]

Clean your battery terminals and any connections around the terminals. Also check the engine ground.

[NautiqueJeff]

Yeah, this is almost certainly a ground issue. Check the battery cables. Often on boats of this era the cables have lots of corrosion going up the wires, way past the terminal connections. I have replaced many sets of battery cables in boats of this era, and it makes a big difference in reliability.

[jmo]

Sounds like your battery needs to be replaced, how old is it?

[fsts2k]

Thanks! Tested the battery and it was decent, it is 4 years old but ended up replacing it. When I used the boat this morning the fuse wiring on the positive battery cable was warm but the fuse had not blown. The terminals are clean and didn’t have corrosion but I get if the wires have corrosion.

Jeff, do you run a new positive and negative all the way back to the engine? I took a measurement on the circuit breakers on the back of the engine and it was showing a 1 volt drop.

Can someone point me to where the negative ground wire is at the engine?

[fsts2k]

Found anther post indicating the negative grounds are on the engine and the aluminum cradle, I will look for those this weekend. In addition I noticed others posting about the shared ground for the dash and the perfect pass; specifically a suggestion to run new grounds for those. I will look there as well.

The warm fuse wiring might indicate resistance due to corrosion.

Over the winter I had the shop replace a heater hose as it had cracked. Another potential is that a ground was moved or adjusted which is causing an issue. Will dig in but appreciate everyones suggestion on which direction to fix things.

[jpwhit]

Anything warm along the electrical path is definitely a problem. Fix that first, that may be the entire issue.

[fsts2k]

Tested all the cables up the fuse box, I think it is a corroded 30 amp fuse in the positive cable from the battery to under the dash. I didn’t have one to replace it but when I cleaned the base of the fuse it immediately improved the connection. It would also make sense that was the issue since it was the area around the fuse holder that was warm in the post above.

[fsts2k]

New fuse.. things are working better but voltage gauge is still only showing 10.5 volts.. might be the fuse holder is corroded.. more testing to be done