It is most likely the regulator/rectifier. It is much less likely to be the stator/altenator itself. The stator is underneath the flywheel and is actuated by permanent magnets in the flywheel. On the regulator there should have been two wires with the same color yellow/white that go into the engine shrouding. These when unplugged should produce around 40 Volts A/C, with the engine at high idle. The regulator is really not testable other than if your stator is putting in the proper volts the regulator should be putting out the proper volts (around 13V) If the regulator is putting out the correct voltage, then your problem is NOT with the charging system. It is either a wiring issue not allowing the charge to reach the battery. Or more likely current draw on the system exceeding the charging capacity. This is usually caused by one of two causes. Additional accessories such as radios, lights, and fans. Blade clutch coil failure drawing more current than it should.
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