Suzuki GA413 Service Manual page 524

Higher Voltage
If voltage is higher than standard value, check ground of brush.
If brush ground is correct, replace IC regulator.
Lower Voltage
If voltage is lower than standard value, proceed to following check.
2) Ground F terminal and start engine, then measure voltage at B
terminal as shown in left figure.
D Voltage is higher than standard value
It is considered that generator itself is good but IC regulator
has been damaged, replace IC regulator.
D Voltage is lower than standard value
Generator itself has problem, check the generator.
Load Check
1) Run engine at 2,000 rpm and turn on head light and heater mo-
tor.
2) Measure current and if it is less than 20 A repair or replace gen-
erator.
OVERCHARGED BATTERY
1) To determine battery condition, refer to Battery section in this
DIAGNOSIS.
2) If obvious overcharge condition exists as evidenced by exces-
sive spewing of electrolyte, proceed to disassembly section of
generator service and check field windings for grounds and
shorts. If problem exists, replace rotor.
3) With engine running at 2,000 rpm, measure voltage.
4) If measured voltage is out of standard value, check brush
ground or IC regulator.
CHARGING SYSTEM 6H-9