•
Unsatisfactory performance
If the governing system functions poorly, perform the following tests.
•
Insufficient magnetic speed sensor signal
A strong magnetic speed sensor signal will eliminate the possibility of missed or extra pulses. The
speed control unit will govern well with 0.5volts RMS speed sensor signal. A speed sensor signal of
3 volts RMS or greater at governed speed is recommended. Measurement of the signal is made at
Terminals C and D.
The amplitude of the speed sensor signal can be raised by reducing the gap between the speed
sensor tip and the engine rind gear. The gap should not be any smaller than 0.020 in (0.45mm).
when the engine is stopped, back the speed sensor out by 3/4 turn after touching the ring gear tooth
to achieve a satisfactory air gap.
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SYMPTOM
TEST
PROBABLE FAULT
Actuator goes to full fuel. then, disconnect speed
sensor at Terminals C & D.
•
If actuator still at full fuel speed control
unit deffective.
•
If actuator at minimum fuel position
errorneousspeed signal.
Check speed sensor data.
1. If the voltage reading is 4.0to6.0VDC
a) SPEED adjustemnt set above desired speed
b) Defective speed control unit.
2. If the voltage reading is above 6.0VDC.
a) Actuator or likage binding.
3. if the voltage reading is below 4.0VDC.
4. Gain set too low.
If the voltage is less than 15V for a 24V system,
replace the battery if it is weak or undersized.
1. Actuator or battery wiring in error.
2. Actuator or linkage binding.
3. Defective actuator.See actuator troubleshooting.
4. Fuse opens. Check for short in actuator or
actuator wiring harness.
1. If voltage measurement is within approximately 3
volts of the battery supply voltage, then fuel
control restricted from reaching full fuel position.
Possibly due to interference from the mechanical
governor, carburetor spring or linkage alignment.
2. Speed setting too low.
Engine
overspeeds
Actuator does
not energize
fully.
Measure the voltage
at the battery while
cranking.
Manually hold the
engine at the desired
running speed.
Measure the DC
voltage between
Terminals A(-)&F(+)
on the speed control
unit.
Do not crank. Apply
DC power to the
governor system.
Momentarily connect
Terminals A and F.
The actuator should
move to the full fuel
position.
Measure the actuator
output. Terminals
A&B, while running
under governor
control
Engine remains
below desired
governed speed.