Low charging rate, Ideas?

tom3

tom3

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Basics: Craftsman GT riding mower 917.255980. Kohler 18hp opposed twin MV18s Magnum, spec 58556. 12 volt 15 amp single circuit type charging system. Electric blade clutch and headlights are powered from the battery.

Checks at 3000 rpm give 29 volts AC (regulator unhooked), 13.8 volts and 4 to 5 amps max with low battery charge. With blade clutch engaged I'm getting one amp or less to the battery. Did replace the voltage regulator, cleaned all terminals, checked for loss at cables and wires. Checked the charging coils, 0.5 ohms resistance. no continuity to ground. Didn't pull flywheel. All looks good except output. Have to recharge the battery a couple times through the summer. Had this mower for 10 or 12 years, has never charged up to spec. What am I missing?
 
EngineMan

EngineMan

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From the readers you have given the charging system is working fine, my only suggestion would be to replace the battery or try another one.
 
I

ILENGINE

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The next step for me would be to check the amp flow on a wire ran directly between the regulator and the battery bypassing the wiring harness on the mower. Could be a wire someplace through the harness that for some reason doesn't have the ability to carry amperage under load

Could either run a wire between those two point with a clamp amp installed on the wire, or install an amp gauge that can handle the 15 amp load that could be generated in the newly installed wire.
 
tom3

tom3

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Well, tried that, about 1 amp between the reg. and the battery terminal. One stone left to turn over, pulled the flywheel. Expected a real chore, not too bad actually. But here's what I found:

sears mower stator.jpg sears mower flywheel.jpg



Not sure what to make of this, no room for those magnets run like this, maybe loose and touching each other but still had to be stuck to the flywheel? But, question now is how to clean up those windings without messing up the insulation, and how to attach the magnets back to the flywheel? They do seem to have pretty good magnetic strength anyway. Glad that nothing is broken. Sure ugly under there.
 
B

bertsmobile1

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Some kerro will clean up the stator just fine, remember it can be taken off.

As for the magnets, Taryl Fixes All did a good video on this .
I don't try to glue them back on because I have to offer warranty and the customer pays for a replacement flywheel which is better than me having to pay for both of them is a glued on magnet breaks away.
 
tom3

tom3

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Good ole Taryl saved me some grief with the magnet polarity deal. I checked them with each other, each end attracts each end of the others, seem to be a three section magnet so I glued them on, Gorilla Glue. Got two of them wrong, that glue is tough! Nothing will break it after a couple hours of curing. Had to heat the iron ring to about 500 degrees to get them off. Hope I didn't screw up the flywheel. If I get good results I'll post it, if not I'll keep quiet.

Thanks for the link!!!
 
tom3

tom3

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Got it back together, loaded it up with a car headlight, both beams, the blade clutch, charging the battery, looks like 12 amps with 14.3 volts from the regulator. Probably about all there is with the age of this machine, plenty good enough though. Only took ten years for me to get around to it. Cleaned off the cooling fins good too, pretty well covered up. Also noticed that I can pull a side shield off this flathead twin motor and look up under the flywheel with a small mirror and good light and actually see the magnets. They do stick to the flywheel but I guess they get loose and pull together, lose the magnetic field.
 
EngineMan

EngineMan

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Good to know you fixed it, well done.....:thumbsup:
 
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