Alternator Output Test; Testing Regulator-Rectifier; 10 & 16 Amp Regulated Alternator; Test Regulator-Rectifier - Briggs & Stratton 405777 Series Manual

RED TEST LEAD TO AC OUTPUT PIN
(GREEN CONNECTOR)
BLACK TEST LEAD TO A GOOD GROUND SURFACE
Fig. 19 − Testing AC Output
5. Attach BLACK test lead clip to engine ground.
6. With the engine running at 3600 RPM, AC output
should be no less than:
28 Volts AC − 5 Amp System
40 Volts AC − 9 Amp System
7. If no or low output is found, replace the stator.

Test Regulator-Rectifier

NOTE: Regulator-rectifier will not function unless it is
grounded to engine. Make sure the regulator-rectifier is
securely mounted to engine.
When testing regulator-rectifier for amperage output, a 12
volt battery with a minimum charge of 5 volts is required.
There will be no charging output if battery voltage is below 5
volts.
NOTE: Connect test leads before starting engine. Be sure
connections are secure. If a test lead vibrates loose while
engine is running, the regulator-rectifier may be damaged.
Connect stator wire harness to regulator-rectifier.
1. Insert RED test lead into 10 A receptacle in meter.
2. Insert BLACK test lead into
3. Rotate selector to
4. Attach RED test lead clip to red DC output terminal on
regulator-rectifier, Fig. 20.
BLACK TEST LEAD
POSITIVE BATTERY
TERMINAL
Fig. 20 − Testing Regulator-Rectifier
5. Attach BLACK test lead clip to positive (+) battery termi-
nal.
6. With the engine running at 3600 RPM. The output
should be:
* 3 − 5 Amps − 5 Amp System
* 3 − 9 Amps − 9 Amp System
10
TSM
receptacle in meter.
(DC amps) position.
RED TEST LEAD
RED DC OUTPUT
CONNECTOR
* Depending upon battery voltage. For example, if the
battery voltage was below 11 volts, the output reading
would be 5 or 9 amps, depending upon the alternator
system being tested. If battery voltage is at its maximum,
the amperage will be less.
7. If no or low output is found, be sure that regulator- recti-
fier is grounded properly and all connections are clean
and secure. If there is still no or low output, replace the
regulator-rectifier.
10 & 16 AMP REGULATED ALTERNATOR
The 10 or 16 amp regulated alternator system provides
AC current through two output leads to the regulator-recti-
fier. The regulator-rectifier converts the AC current to DC,
and regulates the current to the battery. The charging rate
will vary with engine RPM and temperature.
Alternator output (10 or 16 amp) is determined by flywheel
alternator magnet size. Therefore, stator and regulator-
rectifier are the same for the 10 and 16 amp system.
WHEN CHECKING THE ALTERNATOR COMPONENTS,
MAKE THE TESTS IN THE FOLLOWING SEQUENCE:

Alternator Output Test

Temporarily, disconnect stator wire harness from regula-
tor-rectifier.
1. Insert RED test lead into
2. Insert BLACK test lead into
ter.
3. Rotate selector to
4. Insert RED and BLACK test lead probes into output
terminals in yellow connector, as shown in Fig. 21.
(Meter test clip leads may be attached to either termi-
nal.)
BLACK
TEST LEAD RED TEST
LEAD
Fig. 21 − Testing AC Output
5. With the engine running at 3600 RPM output should be
no less than:
*
20 Volts − 10 Amp System
*
30 Volts − 16 amp System
*If alternator output test indicates a 16 amp system, see
special instructions for testing regulator-rectifier.
6. If no or low output is found. check for bare wires or any
other obvious defects. If "shorted" leads are not visible,
replace the stator.
receptacle in meter.
receptacle in me-
(AC volts) position.
YELLOW
CONNECTOR
YELLOW CONNECTOR
AC OUTPUT PINS