Generac Power Systems Guardian 5410, Repair Manual

Page: 58 / 82

to Step 2. If the unit does not produce spark or
has weak spark go to Step 4.
2. Do the following:
a. Set a VOM to measure resistance. Connect
the positive (+) meter test lead to Wire 18A
(Wire 18A still removed from the j1 connec-
tor) Connect the negative (-) meter test lead
to a clean frame ground. “Infinity” should be
measured, or 0.5 to 1M ohms, depending
upon the type of VOM used. If “Continuity” is
measured proceed to Step 12.
b. Set a VOM to the diode test range. Attach the
negative (-) meter test lead to Pin Location
j1-14 on the Printed Circuit Board. (Wire 18A
still removed from the j1 connector) Attach
the positive (+) meter test lead to frame
ground. Set the Start-Stop Switch to “START”.
“Infinity” should be measure during crank-
ing and running. If the VOM does not have a
diode test range, set VOM to measure resis-
tance again. “Infinity” should be measured.
3. If Step 1 produced spark and Step 2 tested good,
set the VOM to measure DC voltage. Connect one
test lead to Wire 15 (j1-4) on PCB. Connect the
other test lead to frame ground. Battery voltage
should be measured. Verify that Wire 15 is con-
nected to j1 and that Wire 14 is connected to j1-
5; if reversed the unit will produce no spark.
4. Rotate the flywheel until the magnet is under the
module (armature) laminations (see Figure 7-37).
5. Place a 0.012-0.015 inch thickness gauge
between the flywheel magnet and the module
laminations.
Figure 7-37. – Setting Ignition Magneto
(Armature) Air Gap
6. Loosen the mounting screws and let the magnet
pull the magneto down against the thickness
gauge.
7. Tighten both mounting screws.
8. To remove the thickness gauge, rotate the fly-
wheel.
9. Repeat the above procedure for the second mag-
neto.
10. Repeat Test 55 and check for spark across the
spark tester gap.
11. If air gap was not out of adjustment, test ground
wires.
12. Set the VOM to the diode test position. The meter
will display forward voltage drop across the diode.
If the voltage drop is less than 0.7 volts, the meter
will “Beep” once as well as display the voltage
drop. A continuous tone indicates “Continuity”
(shorted diode). An incomplete circuit (open
diode) will be displayed as “OL.”
13. Disconnect the engine ground harness from the
ignition magnetos and stud connector (see Figure
7-38).
RESULTS:
1. If “Infinity” was not measured in Step 2b, replace
the Printed Circuit Board.
Note: If VOM was set to diode test, a reading of
0.5 volts would be observed when the Start-Stop
Switch is set to “STOP”. If the VOM was set to
resistance, a reading of 0.5 to 1.5M ohms would
be measured. during cranking and running this
reading should go to “Infinity”. Verify that the
meter leads were properly connected as per Step
2 instructions.
2. If battery voltage was not measured in Step 3,
reconnect Wire 15 and Wire 14 to their correct
terminal locations.
A
B
C
ENGINE
GROUND
HARNESS
POSITIVE METER
TEST LEAD
NEGATIVE METER
TEST LEAD
Figure 7-38. – Engine Ground Harness Test Points
Page 56
Section 7
DIAGNOSTIC TESTS