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Cutting Unit Circuit Testing – Gear Pump (P2) Flow Test
(continued)
Hydraulic System: Testing the Hydraulic System
5. For machines with backlap, record the current reel speed setting then set the
reel speed to the highest speed (fully open). The backlap knob on the mower
manifold must be in the MOW position.
Do not engage the cutting units when performing this test.
6. Start engine. Move throttle to full speed (2850 ± 50 RPM).
7. Make sure hydraulic fluid is at normal operating temperature by operating the
machine for approximately 10 minutes.
8. Verify and record engine speed with a phototach.
9. Record tester pressure and flow reading with pump At No Load. Unrestricted
pump output should be approximately 25.7 LPM (6.8 GPM).
Do not close tester valve fully when performing this test. In this
test, the hydraulic tester is positioned before the circuit relief valve.
Pump damage can occur if the fluid flow is fully restricted by fully
closing the tester flow control valve.
10. Verify pump flow Under Load as follows:
A. Watch flow meter pressure gauge carefully while slowly closing the flow
control valve until 12411 kPa (1800 PSI) is obtained on gauge.
B. Record tester pressure and flow readings under load.
11. Open flow control valve fully, move throttle to low speed and turn the engine
OFF.
12. The under load test flow reading (step 9) should not drop more than 15%
when compared to the pump at no load test flow reading (step 10). A
difference in flow of more than 15%, or the inability to achieve specified
pressure may indicate:
A. A restriction in the pump intake line
B. The gear pump (P2) is worn and should be repaired or replaced
13. When testing is complete, remove tester and connect hose to pump fitting.
14. For machines with backlap, return reel speed adjustment knob to original
setting.
15. Check fluid level in hydraulic tank and adjust as necessary; refer to traction
unit Operator's Manual.
CAUTION
CAUTION
Page 4–58
Greensmaster 3120
17230SL Rev C
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