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New stator not generating.

#1

B

bertsmobile1

some long time ago ( Dec 2018 ) I replaced the stator on a 31Q777 0119 - G1 briggs that was fried, literally on a Country Clipper .
Naturally Briggs could not supply a 592830 stator , nil stock n Australia and none due till March 2019.
So I pinched a 592829 of a 21000 and fitted the appropriate rectifier to go with it.

Well the mower ran OK so I decided to leave it till the next service ( big mistake )
SO the Clipper is in the yard now & I have just fitted the new stator & refitted the full wave rectifier.
The new stator I was supplied was 592830 which I was told was what the old one had superceeded to .
Problem is I get nothing out of it and of course being 18 months after purchase I can not send it back.
This is a full wave stator so I should get 30V AC from it but I occasionally get 3V and nothing from the regulator.

Ohmed the stator and get around 0.9 Ω between the pins and nothing between either pin & ground so it should generate by my reckoning
Any ideas before I ring my friendly briggs dealer & get stung for another $ 145


#2

I

ILENGINE

Did you install a new rectifier or reuse the one that was originally on it. I have seen shorted rectifiers take out new stators.


#3

M

mechanic mark

Did you install a new rectifier or reuse the one that was originally on it. I have seen shorted rectifiers take out new stators.
bertsmobile1, I believe you may have the wrong part number for Alternator, see pages 20 & 21 illustrated parts breakdown. Page 21 item 474B part # 592831 Alternator dual circuit


#4

B

bertsmobile1

Did you install a new rectifier or reuse the one that was originally on it. I have seen shorted rectifiers take out new stators.
Rivets,
I reused the original 845907 full wave single output rectifier / regulator that was fitted to the engine the first time it came in.
The owner had been using it with a dead flat & internally shorted battery by jump starting it for a few years.
It came in for a new battery but the stator was burned crispy from running flat strap hours on end.
The owner mows about 8 acres on his property and another 10 on a vacant block a few houses down the road that is owned by a pensioner.
I did a diode check on the old rectifier & it seemed fine as far as one can tell .
It is the full wave 2 input , one output rectifier mounted on the dip stick tube & I double grounded it .
OTOH I can get a new rectifier from the wholesaler so I can add that to the customers bill so I will try that with the new stator.
What I don't get is why when I have continuity through the stator coils & no continuity to ground so the windings should be intact why it does not work.
The resistance between the pins is fairly well the same as the resistance between the pin & ground on the single wire 592829 stator that has been working fine which I assume is the same windings with one side grounded to the laminates.


#5

B

bertsmobile1

bertsmobile1, I believe you may have the wrong part number for Alternator, see pages 20 & 21 illustrated parts breakdown. Page 21 item 474B part # 592831 Alternator dual circuit

Mark
Sorry, I mistyped the engine number in the first post which has now been corrected.
the 31Q777-0119-G1 engine has it's own parts book
According to that the engine should have shipped with the 592829 stator and have either the 794360 or 845907 rectifier fitted.
Well it did have the 845907 rectifier fitted, but that has the 2 pin AC feed for insulated stator windings and the 592829 stator has grounded windings and a single AC output so one would assume the book is wrong as it does not plug into the 845907 rectifier unless there is some sort of a splitted sub loom as the plugs are different ( 2 pin rectangular & single pin round )


#6

M

mechanic mark

Pages 20 & 21, thanks bertsmobile1


#7

B

bertsmobile1

Yep that is the book I am using .
Only questionable thing is that book is a 2018 publication and I have a 2008 engine so perhaps there have been changes but the only one I noticed was achange to the magnetos.


#8

I

ILENGINE

Something else to consider is the magnets have come loose from the flywheel. Low chance but could be possible. I had a Kohler about a month ago that had 13 volts from the stator thinking I had a bad stator and it was putting out that voltage with all the magnets stuck to the stator ring.

The shorted rectifier that I had was shorted to ground on one of the two stator connection terminals in the two wire plug.


#9

B

bertsmobile1

I checked them before I put the flywheel back on when I cleaned all of the dust & debris from around them.
I would really like to know what those 4 lines of glue ae because like you I have several Kohler flywheels with loose magnets.
Ordered a new rectifier today because having a good one in stock won't hurt or break the bank, in fact I ordered one of all 3


#10

StarTech

StarTech

The problem is that you first posted that you had a 31Q777-0111-B1 then later you have it as 31Q777-0119-G1.

Yes the 31Q777-0111-B1 had a dual circuit stator and the 31Q777-0119-G1 had the tri-circuit (5/9 amp) stator. So the question is which engine do you actually have?

Also the 592830 is 10/13/16 amp stator. As mention check your flywheel magnets. Usually has two black or yellow wires.

Also of one could measure the resistance of the 10/13/16 stator it would be helpful. All four Briggs engine on the yard currently are the tri-circuit version with rectifier/voltage regulator so I can't do it here.

As re-gluing the magnets I use two ton epoxy and use spacers to keep the magnet in place until the epoxy is cured.


#11

B

bertsmobile1

Opps, type0 in the first place so I go back & correct it
Engine number should be - G1.
The original stator had 2 yellow wires with a white 2 pin plug
Mower has no AC circuit so the rectifier has a single red DC output with a white connector split at the mower plug with a jumper.
The original stator looked the same as the replacement , with 4 pairs of coils.

According to the colour coding on the alternator chart that I have it is the 20 amp regulated stator & rectifier .
Should have measured the magnet size before the flywheel went on but was not expecting the thing to fail to generate.

So remeasured the resistance which when subtracting the resistance of the meter which does not have a zero correction the stator comes out 0.9 Ω
This is the same value I get from measuring the 592829 stator which was working from the single AC output to ground.
This is what I expected as the two coils are supposed to be identical except one has grounded coils & the other has insulated coils.
I am not too bad with electrics but getting ones head around Briggs alternators with all of the variations and part number changes tends to do the head in.


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