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TROUBLESHOOTING & REPAIR
F-32 F-32
RANGER 305D
ENGINE THROTTLE ADJUSTMENT TEST (continued)
Vibratach Method
A Vibratach is used to measure the vibrations
caused by the running engine. It can be posi-
tioned anywhere where the engine vibration is
reasonably strong. The best results will likely
be obtained by opening the top engine cover
and placing the Vibratach directly against the
top of the engine.
Read and understand the manufacturerʼs
instructions for the Vibratach.
1. Start the engine and place the idle switch in
the “HIGH IDLE” position. Make sure that
there is no load on the machine.
2. Position and adjust the Vibratach; it should
read between 3525 and 3675 RPM.
3. Move the idle switch to the “AUTO IDLE”
position and wait for the idle solenoid to
energize, and the engine RPM to drop and
stabilize at the low idle RPM.
4. Position and adjust the Vibratach; it should
read between 2400 and 2500 RPM.
If either of the readings is incorrect, pro-
ceed to the “THROTTLE ADJUSTMENT
PROCEDURE” later in this section.
THROTTLE ADJUSTMENT PROCEDURE
IMPORTANT: Both the high and low idle set-
tings are adjusted at the solenoid. DO NOT
ATTEMPT TO ADJUST THE STOP SCREWS
ON KUBOTAENGINE.
The high speed stop screw on the engine is forover speed protection only. It is set to 3800RPM at the Kubota factory and is wire locked inplace to prevent tampering
.
1. Check that the linkage attaching the sole-
noid to the engine speed control lever is
properly aligned and in good condition. It is
more important that the solenoid linkage be
more precisely aligned when in the high
speed (de-energized position).
2. Check to be sure the spring located inside
the rubber boot is not broken or missing. In
the default, (de-energized) position the
spring should be holding the solenoid in the
high speed position. SeeFigure F.6.
NOTE: Low idle RPM must be set, and the
adjustment nuts tightened, before the high
idle RPM is adjusted.
Low Idle adjustment:
1. With engine running and no load applied to
the machine, place the idle switch in the
“AUTO IDLE” position. Wait for the idle
solenoid to energize and the engine speed
to drop and stabilize to low idle RPM.
2. If the low idle RPM requires adjustment,
loosen the low idle adjustment jam nuts.
Turnboth nuts so they are clear of the swiv-
el fitting. Rotate the swivel fitting until the
engine speed has been set to between
2400and 2500 RPM. Hold the swivel fitting
in position while tightening the first jam nut
against the swivel fitting, and then tighten
the second jam nut against the first. See
Figure F.6.
3. Re-check the low idle RPM, and then pro-
ceed to the high idle adjustment.
High idle adjustment:
1. With engine running, place the idle switch
in the “HIGH IDLE” position. The solenoid
should immediately de-energize, allowing
the engine to increase to high idle speed.
2. If the high idle RPM requires adjustment,
loosen the high idle adjustment screw jam
nut and turn the adjusting screw until the
engine speed is between 3625 and 3675
RPM. Hold the adjusting screw in position
while tightening the jam nut against the
solenoid plunger. See Figure F.6.
3. Re-check the high idle RPM.
4. Close the engine service access doors and
shut off the engine.