Generac Power Systems 8 kW LP User Manual

Page 129

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sEctioN 4.4

DiaGNostic tEsts

Page 127

PROCEDURE:

1. Set a VOM to measure DC voltage.
2. Remove Wire 13 from the Starter Contactor Relay located

under the printed circuit board.

3. Connect the positive (+) meter test lead to the Wire 13

connector. Connect the negative (-) meter test lead to a

clean frame ground. Battery voltage should be measured.

4. Reconnect Wire 13 to the SCR.
5. Remove Wire 16 from the SCR. Connect the positive (+)

meter test lead to the SCR terminal from which Wire 16

was removed. Connect the negative (-) meter test lead

to a clean frame ground.

6. Set the AUTO-OFF-MANUAL switch to MANUAL.

Observe the meter reading. Battery voltage should be

measured. If battery voltage is not measured, proceed

to Step 7.

7. Set the VOM to measure resistance.
8. Remove Wire 0 from the SCR. Connect the positive (+)

meter test lead to the disconnected Wire 0. Connect

the negative (-) meter test lead to a clean frame ground.

CONTINUITY should be measured.

RESULTS:

1. If battery voltage is not measured in Step 3, repair or

replace wiring between the starter contactor relay and

the starter solenoid.

2. If battery voltage is not measured in Step 6 and

CONTINUITY is measured in Step 8, replace the starter

contactor relay.

3. If battery voltage is measured in Step 6 refer back to

flow chart.

teSt 64 – teSt Starter contactor

(SinGle cylinder enGine)

DISCUSSION:
The starter contactor (SC) must energize and its
heavy duty contacts must close or the engine will not
crank. This test will determine if the starter contactor
is in working order.

PROCEDURE:
Carefully inspect the starter motor cable that runs
from the battery to the starter motor. Cable connec-
tions must be clean and tight. If connections are
dirty or corroded, remove the cable and clean cable
terminals and terminal studs. Replace any cable that
is defective or badly corroded.
Use a DC voltmeter (or a VOM) to perform this test.
Test the starter contactor as follows:

1. Connect the positive (+) meter test lead to the starter

contactor stud (to which the red battery cable connects).

Connect the common (-) meter test lead to a clean frame

ground. Battery voltage (12 VDC) should be indicated.

2. Connect the positive (+) meter test lead to the starter

contactor stud to which the starter motor cable attaches

(see Figure 8 or Figure 9). Connect the common (-) test

lead to frame ground.

a. No voltage should be indicated initially.

b. Set the AUTO-OFF-MANUAL switch to MANUAL.

The meter should now indicate battery voltage
as the starter contactor energizes.

16

TO STARTER

stEP 2

TEST POINT

stEP 1

TEST POINT

13

TO BATTERY

13

TO FUSE (F1)

0

TO GROUND

56

TO ECB

Figure 8. The Starter Contactor (Single Cylinder Units)

RESULTS:

1. If battery voltage was indicated in Step 1, but NOT in

Step 2b, replace the starter contactor.

2. If battery voltage was indicated in Step 2b, but the

engine did NOT crank, refer back to flow chart.

STARTER

CONTACTOR

STARTER

MOTOR

stEP 2

TEST POINT

stEP 1

TEST POINT

Figure 9. The Starter Contactor (V-twin Units)

DC CONTROL

Part 4

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