Charging system

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sky89vette

Forum Newbie
Battery will hol charge from external charger but the charging system will not charge. When the pro is engaged the amp meter goes negative.
Stator is putting out 32-45 ac volts. New regulator installed. Seems to be losing the contact on the charging wire (blue) from the regulator where it goes to the relay. Has fried a couple pto switches and a key switch.
1. Could the problem be the starter relay ? (the engine cranks and works for an hour before battery is depleted.)
2. could it be a bad starter switch?
fyi -The mower has been boosted from a battery
thanks for any ideas here. the mower is a scag sthm 3 wheeler with a Koehler 23 command pro.
 
The ac voltage sounds about right, the DC output should be around 14volts or thereabouts , there is one terminal on the voltage regulator for this output , your volt meter should register DC voltage when the machine is revving up to operation speed.
The starter relay only comes into play when the ignition switch tells it to crank over then drops off.
You can test your starter switch with a test light, to see if it's output is 12volts .
you can pull the wire off the solenoid and try the key switch with the test light attached to prove it's working or not
 
sky89vette said:
Battery will hold charge from external charger but the charging system will not charge. When the pro is engaged the amp meter goes negative. Stator is putting out 32-45 ac volts. New regulator installed. Seems to be losing the contact on the charging wire (blue) from the regulator where it goes to the relay. Has fried a couple pto switches and a key switch.
Click to expand...
So the mower's own charging system is not working. The most likely suspect is the rectifier-regulator because it contains electrical diodes that are easily damaged by electrical accidents or simple age. Since you tell us there have been previous "fried" components, it sounds like the the rectifier-regulator was also damaged at the same time.

sky89vette said:
1. Could the problem be the starter relay ? (the engine cranks and works for an hour before battery is depleted.)
2. Could it be a bad starter switch?
Click to expand...
Frankly speaking, NO !! Neither of these components are part of the "charging system". Nor does the output of charging system pass through either of these components. Battery charge is what you are missing, so common sense says the first thing to measure is the DC OUTPUT of the charging system. It should be at least 2A of current at around 14.4VDC when the engine is running at moderate to full RPM.
 
Okay with it frying a couple PTO switches it more likely that the PTO clutch is partially shorted. I have seen to up to 20A (PTO switches are rated for 5 to 10 amp, depending who makes them) and still operate. Normally PTO clutches only pulls up to 5 amps with around 3 amp being closer to normal.

Kohler engine usually don't have more than a 15 amp system. Would the both model and spec numbers of the engine to look it up.
 
Amp meter goes minus when pto is engaged. Pictured is model number and serial number.
 

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Got new regulator and getting blue wire contact to the relay. Added pto clutch as it was over 10 ohms resostence. Now the mower sputters and cut after engaging a new pto clutch. Set the gap at .015 any suggestions. should I burnish clutch w/o belt attached?
 
Most times you need to rev it up almost full throttle when engaging the clutch , then you can moderate your speed to where you want it
 
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