369
TRIM AND TILT
TROUBLESHOOTING
13
Remove the manual release valve. Install pres-
sure gauge and adapter “B” to check problems in
the DOWN circuit. Cycle the unit down and up
several times to purge air. With all rods fully
extended, run the unit down momentarily to
reduce pressure. Check fluid level again, and
add fluid if necessary. Remember that all rods
must be completely extended to check fluid level.
Starting with the tilt cylinder fully extended, run the
unit DOWN.
• The gauge should show 0 to 200 psi (0 to 1379
kPa) as the tilt cylinder is retracting.
• The gauge should show approximately 800 psi
(5516 kPa) as the unit stalls.
• Release the switch and watch for a pressure
drop. The stall pressure reading must not drop
more than 200 psi (1379 kPa) after motor stops.
If results vary from the above limits, there is a
problem in the DOWN circuit. Refer to MODES
OF OPERATION (Three Piston System) on
p. 359 for circuit description.
Check fluid level again and add fluid, if necessary.
Single Piston System
Use the following guidelines to check a single pis-
ton trim/tilt unit that is not working correctly.
Cylinder Leakdown:
• Manual release valve seals
• External leaks
No reverse lock:
• External leaks
No operation, motor runs:
• Manual release valve open
• Fluid level low
• Pump coupler
• Hydraulic pump
No tilt down:
• Manual release valve
• Fluid level
Slow performance:
• Manual release valve
• Fluid level low
• Mechanical binding
• Electric motor
• Hydraulic pump
Unit locked in tilt up:
• Mechanical binding
• Hydraulic pump
CAUTION
After tests are complete, run the unit up,
then down momentarily. Cycle the unit
down and up several times to purge air.
With all rods fully extended, run the unit
down momentarily to reduce pressure.
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