Test 28 - Remove Shutdown Wire; Test 27 - Check / Adjust Governor - Generac Power Systems GP Series Diagnostic Repair Manual

Section 4 Engine Diagnostic Tests
A keyway is provided for alignment only and
theoretically carries no load.
NOTE: If flywheel key becomes sheared or even partially
sheared, ignition timing can change. Incorrect timing can
result in hard starting or failure to start.
Test 28 – Remove Shutdown Wire
General Theory
Wire 18 on all engines is used to shut down the unit when
either the switch is placed in OFF, or a low oil condition
occurred. A ground is applied to the magneto in both
instances which inhibits spark and shuts down unit. If a
short to ground exists on this wire, the engine will be
inhibited from producing spark. This test will check the
integrity of the wire.
NOTE: The shutdown lead on units with the 389cc
engine will not be identified as Wire 18. Refer to
4-18 for identification of location.
OFF-ON SWITCH
Figure 4-18. Shutdown Lead (389cc Engine)
Procedure
Turn off fuel supply.
1.
Remove flywheel cover so magneto is exposed.
2.
See 4-19. Disconnect Wire 18 from
Figure
3.
magneto.
Repeat Test 19 – Check Ignition
4.
Figure 4-19. Wire 18 (410cc Engine)
32
Figure
MAGNETO
SHUTDOWN HARNESS
008738
WIRE 18
Spark.
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Results
If spark now occurs, Wire 18 has a short to ground.
1.
Trace Wire 18 back to START-RUN-STOP switch
and Oil Pressure Module (if equipped).
If spark still does not occur, refer to flow chart.
2.
Test 27 – Check / Adjust Governor
Generator AC frequency output is directly proportional to
the speed of the rotor. A two-pole rotor (having a single
north and a single south magnetic pole) will produce an
AC frequency of 60 hertz at 3600 RPM.
The AC output voltage is generally proportional to AC
frequency. A low or high governor speed will result in a
correspondingly low or high AC frequency and voltage
output. The governed speed must be adjusted before any
attempt to adjust the voltage regulator is made.
Procedure
See Figure 4-20.
Loosen governor clamp bolt (A).
1.
Hold governor lever (B) at its wide open throttle
2.
position, and rotate governor shaft (C) as follows:
•
Counterclockwise as far as it will go on 389/208/
196cc Engines.
•
Clockwise as far as it will go on 410cc Engines
Tighten governor lever clamp bolt to:
3.
•
110 in-lbs (12.4 Nm) for 389/208/196cc Engines.
•
70 in-lbs (8 Nm) for 410 Engines.
Figure 4-20. Governor Adjustment (410cc Engine)
Figure 4-21. Governor Adjustment (389cc Engine)
A
B
C
D
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C
B
D
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Diagnostic Repair Manual
A