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Which needs replacement? Stator or Regulator


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#1 dmorrill22 OFFLINE  

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Posted July 30, 2015 - 04:33 PM

I am trying to track down a no-charge condition on a Briggs 25hp engine.

Here are the numbers of the engine:
Model #: 445777
Type 0112 E3

Background Info:
The engine will start and run fine. It is on a Husqvarna tractor with an electric PTO. After running for a while with the PTO engaged, the blades will shut off and the battery eventually dies.

Here are the results of some multi-meter tests I have done:

Battery voltage with engine off: 12.5 VDC
Battery voltage with engine running: 12.5 VDC

With the stator disconnected from the regulator, I connected the two respective wires to my multimeter. The Briggs manual calls for 20 VAC across these two wires, where I am only getting 15. With one multi-meter lead connected to a clean ground, and the other connected to a stator wire, I got 7.1 and 7.6 VAC from either stator wire. With the multimeter set to DC volts, I tested the output from the regulator (red wire, no diode) and got only 3 VDC.

On the OHM setting, I got 1-2 ohms across both terminals. Each terminal to ground showed there was no short (multimeter had no reading).  The ohm checks tell me that the stator windings aren't broken, and there is no short, but I still don't know if the stator is defective.

All of this has led me to think the stator is bad, but I can't completely discount the voltage regulator. 

Are there any further tests I should be doing?

For reference, the engine has the following stator and regulator setup:

10 Amp DC Regulated

Stator #695466 (Two Black Wires)

Regulator #691185 (Two Yellow Wires, One Red)



#2 New.Canadian.DB.Owner OFFLINE  

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Posted July 30, 2015 - 05:02 PM

JAWAG but, if the stator isn't putting out enough voltage, the regulator can't regulate what isn't there.  I would pull the flywheel and clean/check the magnets (assuming they still hide those parts under the flywheel).


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#3 KC9KAS OFFLINE  

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Posted July 30, 2015 - 05:09 PM

Sounds like your test methods were correct, and I too think it is a stator problem, not regulator.
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#4 larrybl ONLINE  

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Posted July 30, 2015 - 07:02 PM

At what RPM was the 15 VAC showing up? Briggs specifics 22 VAC @ 3600 RPM, with battery connected and lights off.

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#5 dmorrill22 OFFLINE  

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Posted July 30, 2015 - 07:21 PM

Larry,

 

The tests were conducted at wide open throttle.

 

Thanks,

Doug


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#6 larrybl ONLINE  

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Posted July 30, 2015 - 07:25 PM

Another vote for a stator replacement, and check the magnets while you are in there.


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#7 WNYTractorTinkerer ONLINE  

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Posted July 30, 2015 - 09:27 PM

Another vote for a stator replacement, and check the magnets while you are in there.

I concur!!   :thumbs:


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#8 superaben OFFLINE  

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Posted July 30, 2015 - 10:19 PM

I hate to disagree with the consensus opinion... but I'm voting to replace the regulator first.

 

Here is my test procedure.  Nothing fancy, but it always works for me. 

 

Disconnect the red plug from the regulator/battery connection.

 

Turn the key on.

 

Do you have 12.5 volts at the red plug from the wiring harness of the tractor?  If you do, then proceed.  If not, you have an issue elsewhere... possibly a bad key switch.   If you want to be sure, run a jumper from the hot terminal of the battery and plug it into the red regulator connection and see if the battery charges.  If it does, it is a tractor issue: the regulator and stator is good, the tractor wiring is not.

 

Disconnect the yellow plug from the stator/regulator connection. 

 

Start the engine, and measure across the terminal reading AC volts.  You should have 15-35.  Anything higher will smoke the system.  Anything lower than about 10 will not excite the regulator enough to make anything happen. If you have 15, I would say you are good to be honest.  I would replace the regulator and see if that fixes it.

 

If you have 15-25 AC volts across the yellow plug and 12 DC at the red plug, but no charge... the regulator is toast.

 

Regulators fail many many times more than stators. 

 

Ben W.


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#9 JDBrian OFFLINE  

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Posted July 31, 2015 - 07:06 AM

Sounds to me like it's the regulator. One more test will tell you if your stator is good. The real test is if it will supply current at 15volts output. I would find a load to connect across the stator output. 15volts RMS is enough for the regulator to work, but with it disconnected you are measuring an unloaded stator. By connecting a load you will be testing it's ability to provide output current. If the voltage falls to a low value under load then the stator or the connections to it are a problem. I think stators are much more expensive than regulators and harder to change. A power resistor would be a good load if you had one. A 2 ohm resistor for instance. If you can't find something like that you could try a light bulb. If the stator is good it will put close to 15 volts out under load and the bulb will not last long. Put a voltage meter across the stator output and watch the voltage under load. Even a tail light bulb from a car would work. 

  You need to also check the electrical connection from the engine to the regulator case and to the battery - terminal.

Even a small amount of resistance there will cause issues with the charging circuit. Good luck! 


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#10 Bruce Dorsi OFFLINE  

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Posted July 31, 2015 - 07:23 AM

While we mostly concentrate on the positive side of the circuitry, let's not forget the other side!

 

There must be a good connection between the negative terminal of the battery and the engine block. 

 

Paint, rust, corrosion, etc., can cause resistance in the charging circuit. 

 

 

 

 

(edited for spelling)


Edited by Bruce Dorsi, July 31, 2015 - 08:49 AM.


#11 crittersf1 OFFLINE  

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Posted July 31, 2015 - 07:27 AM

I'd place my bet on the regulator.



#12 KC9KAS OFFLINE  

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Posted August 04, 2015 - 04:52 PM

Just wondering....did you get it figured out?

What was the problem?

Who's diagnosis was correct?






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