2005 F115 not charging. Stator?

[Coreylaker]

I fix one issue and up pops another. This time it appears to be a charging issue. Should not my motor continue to run when the battery is disconnected? I recently rebuilt it with a re-manufactured head and short block. A small leak was misting the right side of the motor during its first run and it died after about 15min. Water problem fixed, turned out to be a loose ground wire and I'm good to go. I don't run the boat much and this weekend I end up with a dead battery. I start it and just to see whether it was charging I started it, got beyond a slow idle and disconnected the battery. Dead she goes.
Does anyone have any troubleshooting advice for me?
Thanks,
Mark

[99yam40]

Just like a lot of newer autos it is very bad to have a loose battery connection or to disconnect it while running.
Charge up the battery before starting it again and see if you fried something.
Something drained the battery so you need to be looking for what did that also

[boscoe99]

Most Yam EFI four strokes won't run with the battery disconnected. They may run for a short while but as soon as the throttle is advanced they will stop running.

Put a voltmeter on the battery. Should read about 12.7 volts if fully charged. Start the motor and run it at a fast idle. Voltage seen at the battery should be around 14.5 volts. That tells you that the charging system is working.

Don't try and fix something that is not broken.

[Coreylaker]

Thank you for the replies. The battery is only a year old and is a big one. Could it be bad, of course, but I find it unlikely. This boat is at my lake cottage a few hours from home and in my haste to get back to work I didn't take time to check the voltage while running. Something to add to the equation is stalling and rough idle, which to me is further evidence that I may have a charging issue. Does this additional info change the prognosis?
Mark

[TownsendsFJR1300]

PM sent earlier.

+1 on both ^^^.

At this point, charge the battery fully and get it LOAD tested. Most auto parts stores, Walmart will check it for free..

If you have an open circuit, slow steady draw(say bilge pump stuck on), that's the best way to ruin a battery...

Once / if the battery passes, as noted above (and in my PM) check voltages running(battery hooked up). Hopefully you didn't cook the voltage regulator or stator.

If the voltages are way above 14.5, you at least likely toasted the VR.



**Please read this thread, especially post #19 here, same procedure for checking an open circuit (but on a motorcycle)

Battery leads reversed, what now? - Page 2

[Coreylaker]

I am very concerned that I toasted something when my stalling issue turned out to be a loose ground on the harness nearest the fuses.
Every time I discover there's an issue it seems to be right before I have to make the 3hr drive back home so I don't have time to properly troubleshoot. Any clue how much parts will cost me if it turns out something is fried? I'm confident the battery is good as it's a big one, only a year old and I use a disconnect switch religiously every time I shut it down.

[TownsendsFJR1300]

You need to get a voltmeter, start getting some #'s and digging.

Until you do that, your just going to throw parts at it, chase your tail, etc..

[Coreylaker]

Oh, I understand, but the curiosity is killing me!

[99yam40]

I would be concerned about misting water into the intake and then dying.
any moisture inside a motor can cause rust

[zenoahphobic]

I would be concerned about misting water into the intake and then dying.
any moisture inside a motor can cause rust

I think the OP solved the "misting" by tightening the earth strap bolt (presumably loose cover?).

But you may be on the right track that water may still be around in the electrics, causing direct shorting or corrosion in electrics.

[Coreylaker]

The water issue was a leaking anode grommet which was solved.

[Coreylaker]

As I had expected, my battery tested good. I started the motor and no matter the RPM I'm getting 12V.
What are my next steps to troubleshoot the issue?
Thanks in advance.

[99yam40]

follow the procedures in service manual for testing the output and input of rectifier/regulator.
Need the proper testing meter the manual calls for to see if things meet specs

[Coreylaker]

Thank you, but unfortunately I don't have the service manual. It is clearly not charging at all.

[rodbolt17]

its not a difficult system.
it has 3 basic parts,just like ANY A/C generating system.
a rotor,(flywheel) with magnents that rotate around a stationary set of coils(stator) that feeds an A/C current to a regulator/rectifier.