1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 272Get this manual
9-19 LOWER UNIT CHECKING PROPELLER SHAFT THRUST PLAY See the "GEARSSHIMMING AND ADJUSTMENTCHECKING PROPELLER SHAFT THRUST PLAY" section on page 927
LEAKAGE CHECK To check for oil seal or o-ring leakage, use oil leakage testerBefore leakage check, temporarily fasten the driveshaft bearing housing to gearcase using two bolts and nuts (placed through the two diagonally opposite gearcase mounting holes)
Apply the specified pressure through the oil level hole and rotate the drive and propeller shaftsIf pressure does not fall, sealing performance is correct09950-69512Oil leakage tester 09952-99310Air pump Leakage test pressure100 kPa (1.0 kgcm2, 14.2 psi)