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dogthenine
05-07-2007, 10:01 PM
I am having a battery (charging) problem. I was having to charge/jump-off my lawnmower (Murry with briggs and stratton engine) everytime I used it. Anyway, I bought a new battery a 1.5 weeks ago, and the lawnmower started right up. I used it for one day, and it sat for 9 days. Today, I went to start it and it wouldn't start. The starter will turn the motor over (slowly) a time or two and then stop at the bottom of the stroke. (like a weak battery). But when I jump it off it will turn over until it starts. What is my problem? Is it the Stator?

Thanks,
dogthenine

Bill Kapaun
05-07-2007, 10:52 PM
You are jumping what to what?

http://www.lawnsite.com/showthread.php?t=144040

dogthenine
05-07-2007, 10:59 PM
By "jumping-off" I mean I am using my battery charger's 100A engine start mode hooked to the Positve and Negitve terminals on the battery.

Engine model--28N707

Is this what you are refering to?

Bill Kapaun
05-08-2007, 04:53 AM
"Is this what you are refering to?"

Yes to both, I didn't know if the Murray was the jumper or the jumpee:)

Do you have a voltmeter? Even a cheap one From Radio Shack can be handy.

Look at the wires coming out from the alternator/shroud.
How many and what color are they?
Ditto the the wires from the connector to the rest of the tractor.

dogthenine
05-08-2007, 12:41 PM
"Is this what you are refering to?"

Yes to both, I didn't know if the Murray was the jumper or the jumpee:)

Do you have a voltmeter? Even a cheap one From Radio Shack can be handy.

Look at the wires coming out from the alternator/shroud.
How many and what color are they?
Ditto the the wires from the connector to the rest of the tractor.


I do not have a voltmeter.
The wires comming out of the shroud are red and black. There are three wires going to the rest of the tractor--red, white, and black (which goes to the starter).

Bill Kapaun
05-08-2007, 03:05 PM
From your description-
This is something somebody sent me a long time ago-

This is a dual circuit Stator 3 AMP DC unregulated, 5 AMP AC, (this is the only unit that runs AC out to the lights) with the diode for the DC at the connector, this stator uses a black and red wire from under the flywheel to a white connector then the wires change to red (DC) and white (AC), the diode is encased in the connector they say.

If this description is correct, your headlights would only operate when the motor is running.
If this is correct, do they operate now? IF not, I'd say the stator is probably toast!

Rig up a 12V test light (tail light type bulb) with a couple clip on leads.
Hook it up to the battery with engine running & not running. Is there a difference in brightness?
If there is, it would appear the system is charging.
IF not-
Unplug connector.
Jumper test light from RED wire from stator & ground. If it is charging, the light should be on when running. If it is on then, but doesn't get brighter in the first test, the diode is probably bad (or bad connection)

Bill Kapaun
05-08-2007, 03:14 PM
Sorry double post

dogthenine
05-08-2007, 03:18 PM
From your description-
This is something somebody sent me a long time ago-

This is a dual circuit Stator 3 AMP DC unregulated, 5 AMP AC, (this is the only unit that runs AC out to the lights) with the diode for the DC at the connector, this stator uses a black and red wire from under the flywheel to a white connector then the wires change to red (DC) and white (AC), the diode is encased in the connector they say.

If this description is correct, your headlights would only operate when the motor is running.
If this is correct, do they operate now? IF not, I'd say the stator is probably toast!

Rig up a 12V test light (tail light type bulb) with a couple clip on leads.
Hook it up to the battery with engine running & not running. Is there a difference in brightness?
If there is, it would appear the system is charging.
IF not-
Unplug connector.
Jumper test light from RED wire from stator & ground. If it is charging, the light should be on when running. If it is on then, but doesn't get brighter in the first test, the diode is probably bad (or bad connection)


Well, first off, my headlights are not plugged up, because the tabs on the plastic lenses broke and the headlights won't stay in now . So, I just removed them. If I understand what you said, then I could hook a light up to the headlight plug. If the stator is working, it should light up. If it doesn't, then the stator is shot. Is this right?

Bill Kapaun
05-08-2007, 03:32 PM
A VERY VERY good indicator.
The R&B wires coming from the stator are AC up to the connector.
The white wire is just an extension of one of the wires coming from the stator, probably the RED one.
It "T"'s off to the headlights (white) AND to the diode (in the connector) to make a "rudimentary" DC for the battery.

I would ASSume you don't have an electric PTO clutch, since 3 Amps wouldn't power it.

dogthenine
05-08-2007, 03:49 PM
A VERY VERY good indicator.
The R&B wires coming from the stator are AC up to the connector.
The white wire is just an extension of one of the wires coming from the stator, probably the RED one.
It "T"'s off to the headlights (white) AND to the diode (in the connector) to make a "rudimentary" DC for the battery.

I would ASSume you don't have an electric PTO clutch, since 3 Amps wouldn't power it.



I will try it this afternoon, and post results. Since I don't know what an electric PTO clutch is, I am sure I don't have it. :dancing:
Thanks for the help so far!

dogthenine
05-08-2007, 04:38 PM
Here are the results:

Headlights are working when engine running.

Tested light on battery both engine on and off no difference in brightness

Tested, with light, both wires comming out of shroud--light came on.

Here is a picture of the wires for reference:

http://img.photobucket.com/albums/v63/dogthenine/wires.jpg

What else could it be?

Bill Kapaun
05-08-2007, 06:26 PM
We NOW KNOW the Stator is GOOD!

Either the diode, which is supposed to be part of the "tractor side" of the connector is bad-
IF it's "shorted", you get AC passing through which will won't charge a DC battery.
If open, you get nothing through.
OR
you have a bad connection in the circuit from the connector to the battery.

Can you disconnect the red wire on the other (non connector) end and isolate it? If so, try the light bulb test between it and ground. That would at least tell you if it's open or not.

This is where a Voltmeter is handy. You can put it on DC or AC and tell which you have. A light bulb doesn't care:)

Restrorob
05-08-2007, 07:07 PM
Bill,

Hope you don't mind the interuption.....

This sounds like the "classic" valves out of adjustment scenario.
The fact that it starts being jumped off is most likely due to more amperage/voltage applied to the starter to bump it past compression stroke, The fact it started the first time with the new battery could have been because it had a higher charge being new right off the shelf or just plain luck.

IMO, It would be time well spent checking the valves since this is a common occurrence.

Just a copy below;

Remove the valve cover then rotate the engine over by hand until you reach top dead center compression stroke, Then remove the spark plug. Once at TDC insert a small screw driver in the plug hole touching the piston and rotate the flywheel clockwise past TDC until you see the screw driver move down inside the hole 1/4". Now loosen the jam screw in the center of the adjustment nut and adjust intake to .003-.005 exhaust .005-.007", Hold the adjuster nut with your wrench while tightening the jam screw. It may take a couple times to get it right because when tightening the jam screw it could throw the adjustment out so check after tightening.

One other thing dogthenine, If the battery does go down in any lawn/garden equipment with these small batteries charge them before trying to start the unit. Pumping 100 amps or even 50 amps into one thats low could blow a strap inside.

Good Luck

Bill Kapaun
05-09-2007, 03:53 AM
Rob, that's certainly possible. Does that engine have a compression release?

"Tested light on battery both engine on and off no difference in brightness
&
Tested, with light, both wires comming out of shroud--light came on. "

That kind of infers the battery isn't being charged, unless the light was too bright to tell the difference.

Dogthenine-
The alternator only puts out about 3 Amps to the battery. Has the battery been fully charged yet?

Restrorob
05-09-2007, 07:03 AM
Does that engine have a compression release?


Yes it does.....

unless the light was too bright to tell the difference.

A test light is good to check for the presence of voltage but a multimeter is needed to get a accurate reading of how much.
Harbor freight has one on sale for $2.99 which is better than none.

dogthenine
05-09-2007, 12:28 PM
Bill, yes the battery has been fully charged.

Rob, I will work on getting a volt meter.

Bill Kapaun
05-09-2007, 03:41 PM
Dogthenine-
As Rob suggested, it would be a good idea to check/adjust the valves.
IF the exhaust valve has too much clearance, the compression release doesn't work. This would make the engine very hard to crank, mimicking a low battery.
If the valve lash is OK, call it "maintenance".:)