Service Manual

CuttingUnitCircuitTesting–GearPump(P2)FlowTest(continued)
Thegearpump(P2)owtestisthelastinaseriesoftestsrecommendedto
determinecuttingunitcircuitperformance.ThistestcomparesuidowatNo
LoadwithuidowUnderLoad.Adropinowunderloadofmorethan15%
indicatesthegearsandwearplatesinthepumphaveworn.Awornpumpwill
by−passhydraulicuidandmakethepumplessefcient.Eventually,enough
uidlosswilloccurtocausethecuttingunitmotorstostallunderheavycutting
conditions.Continuedoperationwithaworn,inefcientpumpcangenerate
excessiveheatandcausedamagetothesealsandothercomponentsinthe
hydraulicsystem.
SpecialEquipmentRequired:
•FlowMeterwithPressureGaugethathasatleasta45LPM(12GPM)
capacity.
•Phototach(non−contacttachometer).
1.Parkmachineonalevelsurfacewiththecuttingunitslowered.Makesure
engineisOFFandtheparkingbrakeisengaged.
2.ReadandadheretotheinformationprovidedinT estingtheHydraulicSystem
(page4–35).
g216911
Figure41
1.Gearpumpsection(P2)
2.Hydraulichose
3.Disconnecthoseconnectiononthebottomofgearpump(P2);refertoFigure
41.
4.Installtesterbetweenthegearpumpandthedisconnectedhose.Make
surethetesterisinstalledinthecorrectowdirectionandthetesterow
controlvalveisfullyopen.
5.Formachineswithbacklap,recordthecurrentreelspeedsettingthensetthe
reelspeedtothehighestspeed(fullyopen).Thebacklapknobonthemower
manifoldmustbeintheMOWposition.
Greensmaster3120
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HydraulicSystem:TestingtheHydraulicSystem
17230SLRevD