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I. PTO Switch Test
The PTO switch is used in the PTO circuit and both safety
interlock circuits: cranking and safety shutoff. To accom-
modate these circuits, the PTO switch has four contacts
actuated by the pull knob. The top and bottom contacts
are common to all models covered in this manual. The
middle N.O. (Normally Open) contacts are used by the
air-cooled engine models and the middle N.C. (Normally
Closed) contacts are used by the liquid-cooled engine
models.
The N.C. contacts will be closed when the PTO switch is
in the OFF position. Pulling up on the knob closes the
contacts, pushing down on the knob will open the con-
tacts.
The N.O. contacts will be open when the PTO switch is
in the OFF position. Pulling up on the knob opens the
contacts, pushing down on the knob will close the con-
tacts these switches.
TEST PTO SWITCH
NOTE: You may want to remove the PTO switch from
the control panel for testing. Refer to the PTO Switch
Replacement procedures located in this section.
1. Pull the wire harness off the back of the switch.
2. Place the PTO switch in the OFF position, knob
pulled up (Figure 43).
3. Set VOM to Ohm. Test the top, middle, and bottom
rows of terminals for continuity (Figure 43.)
4. Place the PTO switch in the ON position, knob
pushed down (Figure 44).
5. Set VOM to Ohm. Test the top, middle, and bottom
rows of terminals for continuity (Figure 44).
Replace a switch that does not pass all tests.
Figure 42. PTO Switch Terminals
A. Top N.C. Terminals (All Models)
B. Middle N.C. Terminals (Liquid-Cooled Models)
C. Middle N.O. Terminals (Air-Cooled Models)
D. Bottom N.O. Terminals (All Models)
A
B
D
Figure 43. Test PTO Switch – OFF Position
PTO Switch – ON Position
No Continuity
Continuity
Continuity
Figure 44. Test PTO Switch – ON Position
7 Electrical System Service
Component Tests
C
No Continuity
PTO Switch – OFF Position
Continuity
No Continuity
No Continuity
Continuity
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