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Gurus needed - ammeter showing discharge


OrangeMetalGuy

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So I was cutting the grass yesterday and noticed the ammeter reading about -10amps (discharging). That was at engine speed used for mowing.

Disengaged the PTO and dropped the throttle back to idle. Ammeter climbs almost to 0.

Did more testing, and here's what it's doing:

1. Shows about -10amps running 3/4 or more throttle.

2. Shows almost 0 at idle

3. At about 3/4 throttle, if I turn on the front and rear lights, the ammeter climbs back to about 0.

4. If I turn the lights off again, the ammeter goes down to about -10amps.

I pulled the battery and cleaned all the terminals as well as those on the ammeter.

Started back up, same symptoms. Grabbed the voltmeter, at idle it's about 12.2volts, at 3/4 throttle it's about 13.5 volts.

I'm stumped. If the battery were really discharging, I don't see how turning the lights on would decrease that, if anything it should make it a lot worse.

I wonder if it's ignition-related instead of charging system related? Would a bad coil do this (something is making the discharge worse as engine speed increases).

Thanks in advance for your help all.

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The ammeter is reading backwards, did you change any wiring lately? If not toss the ammeter and install a volt meter, it's more useful.

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I'm assuming you have the wires backwards on the ammeter. Try switching the wires before getting a new ammeter.

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This could also be an indication of problems in the V/R, trying to prevent the generator from over charging the battery.

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No, the wires are not switched. This just became an issue Friday when mowing, and I hadn't taken the wires off the ammeter since the previous mowing day when the problem did not exist!

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My experience on cars says bad voltage regulator but the last one I bought was 120.00 plus so I'd do as much as I could before blowing your load on that little thing!

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Turn on the key and then the lights (motor not running) and see which way the ammeter needle moves. If it moves to the right (+) the flow through the ammeter is backwards, or the ammeter is messed up internally.

You didn't accidentally drive your tractor through a reverse polarity vortex sm00

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Scott,Your voltmeter check says that the generator is charging properly. I would either reverse the two wires on the ammeter or just remove the ammeter and hook the wires together. I do not have ammeters or voltmeters on any of my tractors. That way there is no gauge to distract me when mowing. I work on the charging system only when the battery will not stay charged.Here is a picture of the dash on my 713S:

Dashplate.jpg

Dashplate.jpg.e24a50f4f6bf5ab522bcc99764cbb71b.jpg

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quote:Originally posted by BLT

Belt drive generator?


id="quote">
id="quote">No, it's a Kohler K341. I am going to go over all the wiring and look for a short. Still can't understand why it would discharge more at HIGHER revs though. I know for absolute that the ammeter wires are NOT reversed because I removed and replaced them one at a time to clean them.I have a new and known good rectifier/regulator and will swap that.I am leaning to a short though somewhere... I remember that on the last mow it almost cut out a couple of times when, and only when, I was moving the hydro control lever with the tractor on a downhill spot. Maybe there is something grounding out.
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I drove A-C's for years, WD, WD45, D17, D19, 190xt, ammeters all. Never understood the ammeter, never consulted it. As long as it starts and the battery is at 12 volts, that's all that matters.... I guess.

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