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Battery Not Holding A Charge

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rivergone

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"I have a 1989 Thompson, with

"I have a 1989 Thompson, with a 3.7 Mercruiser. The battery will not hold a charge. I just replaced it (again). When running, the multi-meter shows 12.3v at the battery. I removed the two yellow stator wires and put the probes on them. No reading. Is this a good test and if so, is the stator shot? If I need to replace it, what brand/model EXTERNAL alternator will work? I figure I can fab a bracket to hold one. I'm a rookie at this and need all the help I can get. Thanks!"
 
"That's what I'm figur

"That's what I'm figuring too.
BUT, I'm trying to verify which is bad, the stator or regulator. I don't want to guess as these things are fairly expensive. Any ideas? Am I testing it correctly?"
 
You need more than just a regu

You need more than just a regular meter to see the output of the stator. You can do a resistance check to see if the coils are shorted to ground.

Be very careful when troubleshooting this charging system. If you disconect the battery or other components after it is running you will probably will fry the regulator.

I do not have the specs with me here to give you more info.

Best fix is a one wire altinator replacement and be done with the original system for ever!! to exspensive to maintain.
 
"All it says "if resistanc

"All it says "if resistance greater then 1 onm, stator is bad", But it should generate AC voltage.I`d guess 15-22 Volts AC"
 
I'll bet the regulator has

I'll bet the regulator has a blown diode in it. That would cause a reduction in DC volts. Stators either work or not.
 
You need a DVA type meter as u

You need a DVA type meter as used when troubleshooting a outboard stators to read the voltage properly. It is a anologe "ac peak holding" senario.

Not 100 % on the actual theory/explanation but I have one of those cheap MERC $100 radio shack quality meters.
 
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