56
With the engine running, minimum values should read:
2500 R.P.M. - 16.0 Volts A.C.
3000 R.P.M. - 19.0 Volts A.C.
3600 R.P.M. - 24.0 Volts A.C.
If the minimum readings are noted, the alternator is okay;
the regulator-rectifier is defective. If less than above
readings, the alternator is defective. See Chapter 9 for
"Disassembly Procedure".
A.C. OUTPUT
YELLOW
32
A.C.
10 Amp Alternator
Models: H & HSK 50-60, HH50-60, HM & HMSK 70-80-100, HHM80,
TVM125-140-170-195-220
CHECKING THE SYSTEM: Unplug the connector at the wiring harness supplied by the OEM. Proceed to make an A.C.
output check. Place one lead of the A.C. voltmeter on the center plug of the connector. Place the other lead to engine
ground (diag. 32).
With the engine running, minimum values should read:
2500 R.P.M. - 16.0 Volts A.C.
3000 R.P.M. - 20.0 Volts A.C.
3300 R.P.M. - 22.0 Volts A.C.
12 Amp D.C. Regulated Alternator
Models: HM80-100, OHM90-110, OHV110-130, TVM220
CHECKING THE SYSTEM: Unplug the connector at the wiring harness supplied by the OEM. Proceed to make an A.C.
output check. Place one lead of the A.C. voltmeter on the center plug of the connector. Place the other lead to engine
ground.
With the engine running, minimum values should read:
2500 R.P.M. - 16.0 Volts A.C.
3000 R.P.M. - 20.0 Volts A.C.
3600 R.P.M. - 25.0 Volts A.C.
VOLTAGE REGULATORS
If a known good or load tested battery fails to maintain a charge, the charging system and the regulator can be checked
using a voltmeter. Set the voltmeter on the 0-20 Volt D.C. scale and connect the probes across the battery terminals as
shown. Note the battery voltage. Start the engine, the voltage reading should increase from the noted battery voltage but
not exceed 15 Volts D.C. If no voltage increase is noted, proceed to make an A.C. voltage check using the applicable
procedure. If the battery voltage exceeds 15 Volts D.C., or the proper minimum A.C. voltage is noted during the check,
replace the regulator.
LOW OIL SHUTDOWN SWITCHES
Check the LOS switch while it is in the engine. The engine
must be level, and the oil level at the full mark. Place the
speed control in the run position. Remove the spark plug
wire from the spark plug. Install a gap type tester connected
to the spark plug wire and a good engine ground. Spin the
engine over using the electric or recoil starter. A bright
blue spark should be seen at the tester. If not, remove the
blower housing and disconnect the LOS lead from the
ignition module. Reinstall the blower housing and spin the
engine over. If spark occurs now, replace the LOS switch.
If no spark is seen, replace the ignition module.
33
Low Oil Shutdown (Brown Wire)
Ground (Black Wire)
Ignition Coil (Green Wire)
ON/OFF LIGHTED ROCKER SWITCH WITH
LOW OIL SHUTDOWN (LOS)
If less than above output, the alternator assembly is
defective. See Chapter 9 for "Disassembly Procedure".
If less than above output, the alternator assembly is
defective. See Chapter 9 for "Disassembly Procedure".
