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#190557 - 06/27/05 05:44 AM Briggs and Stratton 11 HP Generatorproblems
Elegancec Offline
first timer

Registered: 06/16/05
Posts: 4
Hello,
our B&R lawn mower does not start, the starter gets not enough current and the batterie breaks down to 5 V from 12 V before, the battery is full and new and runs perfect in another lawn mower.
If I connect a multitester to the two cables of the stator winding, it's about 2,3 Ohm resistance.
And if I connect one cable to the engine (ground) and the oter one on one stator winding cable, I get 1,9 Ohm.
Is this correct?

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#190558 - 06/27/05 08:54 AM Re: Briggs and Stratton 11 HP Generatorproblems
JasonB Offline
Sharp -Shooter
Carpal Tunnel

Registered: 04/27/04
Posts: 14060
Loc: Cape Spencer, New Brunswick, C...
Hello!

A quick thing to try before troubleshooting the starter electrics. Try removing the sparkplug from the engine. Now, with plug out, try the starter. Does the engine turn at a normal or faster than normal speed for starting? If it does, it could be that the compression release on the engine is not operating correctly, making it hard to turn over. This is fixed by adjusting the valve clearances.

If the engine doesn't turn over quickly, then a component of the starting system is likely failed.

If the engine expells a volume of oil from the sparkplug hole, you may have other problems that lead to oil in the cylinder. Typically oil overfill or carb troubles....

Good luck,

J
_________________________
er, somethin'....

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#190559 - 06/28/05 11:03 AM Re: Briggs and Stratton 11 HP Generatorproblems
Elegancec Offline
first timer

Registered: 06/16/05
Posts: 4
Sorry, I forgot:

The startes does not do anything, no noise no turn, nothing.
So the engine does not have any RPM.

Greetings

EleganceC

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#190560 - 06/29/05 07:12 AM Re: Briggs and Stratton 11 HP Generatorproblems
JasonB Offline
Sharp -Shooter
Carpal Tunnel

Registered: 04/27/04
Posts: 14060
Loc: Cape Spencer, New Brunswick, C...
Ah. Ok, so in the starter circuit, there's a few things. You turn the key, and a circuit is completed. It applies 12v to the coil of the solenoid. Then the solenoid closes a larger switch that applies 12v to the starter motor. So there's three things that could be failed, assuming all teh connectinos are tight and good: Could be a bad starter switch, a bad solenoid or a bad starter. So, break out the volt meter. When the starter switch is turned, does 12v make it to the solenoid. If yes, does the solenoid close the starter's switch? Does 12v get to the starter?

If the solenoid gets it's 12v, but the starter doesn't, the solenoid is bad. Replacement is pretty easy. If the starter gets 12v but doesn't turn, the starter is bad. Replacement is again pretty easy (tho more costly).

Hope that helps.

J
_________________________
er, somethin'....

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#190561 - 07/07/05 12:02 PM Re: Briggs and Stratton 11 HP Generatorproblems
Elegancec Offline
first timer

Registered: 06/16/05
Posts: 4
That did not really fit to the problem.

So I want to describe the complete problem again:

First, if I connect the battery to the ground of the engine and the plus cable to the plus - pole of the battery, a current is about 2,5 Amp through minus-pole of the battery and engine. The Voltage of the battery collapses to 5 V or less.

But if I pull of the red cable of the solenoid, which follows into the engine, I will get enough Voltage on the battery, but if I turn the switchkey, only 5,6 Volt are on the solenoid.

Now I tried to make a connection between blue cable of solenoid and plus pole, but nothing happens, normally the solenoid has to make a noise or the engine must start.
But the key-switch is not the problem, because without it, nothing happens too.
Could it be a leak of Voltage of the stator-ring?

Do you know, how much the resistance is of the coil?
So I want to test, if the coil is not faulty,
I need the resistance of the stator coils and of the coil (magnetron) on the backside.




Edited by Elegancec (07/07/05 12:04 PM)

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#190562 - 07/07/05 01:33 PM Re: Briggs and Stratton 11 HP Generatorproblems
sarabellum Offline


Registered: 08/07/04
Posts: 306

In reply to:

Do you know, how much the resistance is of the coil?




hi
1. Contactor [aka starter solenoid] resistance are on the order of 100 ohms and more ,and must be a higher resistance than a motor [also acts as a generator here]..due to the fact that the contactor is often are held energized .

2.These starter motors will have a resistance in the order of just a few ohms [1-3 ohms] and while this seems alarming at first,you will see that the current is limited to a value below 'burnout' as long as it is ONE: TURNING...and

TWO:
NOT ALLOWED TO BE ENERGIZED FOR TOO AWFUL LONG WITHOUT SOME RELIEF!

This is how car starter battery problems on cold winter mornings of -20F quite often turn out to be BOTH a battery problem at first..then a starter problem later..when the starter is pushed beyond its design limits.

Motors develope what is secretly called CEMF..which is a current in opposition to the applied current,which limits any abnormally high burnout currents ..but only as long as the motor is turning...preferably at rated speed.

Start the machine with a pull rope.


Any battery that measures less than half its rated terminal voltage,AT THE TERMINAL; into a motor that refuses to turn ,is essentially dumping into a low order short, and usually the motor windings will give up first!

You can also measure a low voltage out in the circuit when loose connections are involved and you have essentially a voltage divider ,with the source voltage being divided along all those loose connections in SERIES...with a bit given to each ...as long as a load is present .. but all eventually add up to the source!!!

You can make a drawing of where all the wires connect..KEY... SOLENOID...STARTER/GEN

Then disconnect everything ,and take your ohm measurements .

See if the solenoid will operate/accuate at its rated voltage.

See if the solenoid contactor passes voltage on thru its contact...but remember ..if the contactor contact ..is corroded or burnt on a spot..it may fail under actual load.

Measure the motor start winding for around 1-3 ohms...then see if RAW voltage to its terminals will spin the engine when the plug is out and the compression is low.

Charge the battery tho........even low batteries can measure a healthy voltage when no load is presented...

Just like house 120v will often misteriuosly measure supply voltage when no loads are on.....it will read real nice right on through the loose corroded connection ....but fail under load...and the voltage drops way low.

BTW
If you put juice to a motor and they rotate./.they donot burn out.

On the other hand,if you open the motor and unravel this same winding all the way from your house to the end of the wire....and apply the very same 'juice' to the very same wire......THE WIRE WILL NOW BURN OPEN!..the is no CEMF!


sara
_________________________
"..always clean your shovel" Corinthians 1.10

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#190563 - 09/29/05 02:04 PM Re: Briggs and Stratton 11 HP Generatorproblems
Elegancec Offline
first timer

Registered: 06/16/05
Posts: 4
Hello!

Thanks for everybody who helped me to solve the problem!

But the problem was pretty easy:
The owner before of the lawn mower changed parts of the
cabletree (Kabelbaum in german) and he forgot to install
the diode so in stand by or less, always a current got to the stator about 6 A, so the battery was down and it could not start.
Now I installed a use stator with diode and everything is ok.

But the battery ist down and the charger can not really charge the battery, is it broken or how can I make it work again?



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