Service Manual
Part Numbers
NN10824
Purpose
The low oil pressure switch turns off the oil pressure indicator light and
turns on the hourmeter.
How It Works
The mechanism inside the switch is simply a lever that is moved by a
diaphragm. When there is no oil pressure, the NO switch is open, and the
NC switch is closed. Once oil pressure is present at the pressure switch
orifice, the diaphragm moves the lever and reverses the status of each of
the switches. The switch should change status at 5 psi ± 2 psi.
Testing
1. Disconnect the harness from the switch.
2. Verify the conditions in the table.
3. If the switch is failing intermittently, verify proper oil pressure at idle
(consult your engine manual.) The switch is set to change status at 5
psi ± 2 psi. Also check to ensure that nothing is obstructing the orifice
on the threaded end of the switch.
4. If one or both switches are switching at the incorrect pressure, the
contacts can be adjusted. Use the set screws at the base of each
terminal to get the desired results. Once adjusted, prevent undesired
rotation by sealing with a small amount of fingernail polish.
Part Numbers
116716
Purpose
Typically used to turn on the electric blade clutch and to function as part of
the safety interlock system.
How It Works
Contacts inside this DPDT switch electrically connect various terminals. It
is actually just two SPDT switches tripped by a single lever. One of the
SPDT switches is connected to the electric PTO clutch. When in the off
position, this side of the switch is open. The other half of the switch is
used by the safety interlock system. When the clutch is off, this side of the
switch is closed. This allows current to keep the kill relay energized so that
the mag is not grounded out.
Testing
1. Disconnect the switch from the wiring harness.
2. Verify the conditions in the table.
Switch
Oil Pressure
Oil Pressure NC Switch NO Switch
No Pressure Closed Open
Pressure OK Open Closed
Switch
PTO/Clutch
Lever Condition
Up Open
Down Closed
Glossary
GLOSSARY
3-34 Demystification Guide