Test 24 - Test Off-On Switch; Test 25 - Check Starter Motor - Generac Power Systems GP1800 Repair Manual

DC CONTROL
3. Connect one meter lead to Terminal 2 and connect the
other meter lead to Terminal 1. Actuate switch to the
START position. CONTINUITY should be measured.
4. Actuate switch to the STOP position. INFINITY should be
measured.
5. Keep one meter lead on Terminal 2 and connect the
other meter lead to Terminal 3. Actuate switch to the
STOP position. CONTINUITY should be measured.
6. Actuate switch to the START position. INFINITY should
be measured.
7. Connect one meter test lead to disconnected Wire 0
from Terminal 2 and connect the other meter test lead to
the positive post of the battery, 12 VDC should be mea-
sured. If voltage is not measured, repair or replace Wire
13A between the starter contactor and the START-RUN-
STOP switch.
8. Reconnect all wires to the switch.
RESULTS:
1. If anything but the readings above were measured
replace the START-RUN-STOP switch.
2. Refer back to flow chart.
TEST 24 – TEST OFF-ON SWITCH
DISCUSSION:
The OFF-ON switch applies a ground to the shutdown
harness (Wire 18). By applying a ground to the har-
ness it grounds out the magneto and inhibits spark.
TO FRAME GROUND
OFF-ON SWITCH
OIL LEVEL ALARM
FROM OIL LEVEL SWITCH
PART 3
TEST POINT A
Figure 3. OFF-ON Switch Test Points (389cc Engine)
PROCEDURE:
1. Disconnect Point A from the switch harness (see Figure 3).
2. Connect one meter lead to the female side of the con-
nector and connect other meter test lead to a clean
frame ground.
3. Actuate the switch back and forth between ON and
OFF. CONTINUITY should only be measure in the OFF
position.
RESULTS:
1. If switch failed Step 3, replace the OFF-ON switch.
2. If OFF-ON switch is good, refer back to flow chart.
TEST 25 – CHECk STARTER MOTOR
The following conditions can affect starter motor performance:
1. A binding or seizing condition in the Starter Motor bearings.
2. A shorted, open or grounded armature.
a. Shorted, armature (wire insulation worn and
wires touching one another). Will be indicated
by low or no RPM.
b. Open armature (wire broken) will be indicated
by low or no RPM and excessive current draw.
c. Grounded armature (wire insulation worn and wire
touching armature lamination or shaft). Will be
indicated by excessive current draw or no RPM.
3. A defective Starter Motor switch.
4. Broken, damaged or weak magnets.
5. Starter drive dirty or binding.
00.01
TO FRAME GROUND
SECTION 3.3
DIAGNOSTIC TESTS
MAGNETO
SHUTDOWN HARNESS
WIRE 18
Page 43