2003+ Suzuki DF9.9/DF15 four stroke outboard motors service manual, Page 188Get this manual
LOWER UNIT 8-23
Optimum tooth contact The optimum tooth contact is shown in the figureA shim adjustment may be necessary to obtain the optimum tooth contact pattern# The backlash of the gear should be checked when increasing or decreasing the thickness of the shim to adjust tooth contact
Optimum tooth contact Approx13 of tooth width Approx1 mm HEEL
TOE Convex side
Example (1) Incorrect topside toe contact: Correction measures: Decrease the thickness of the forward gear back-up shim Slightly increase the pinion gear back-up shim thickness# Do not set tooth contact in the top side toe contact positionDamage and chipping of the forward and pinion gear back-up may result
EXAMPLE OF INCORRECT Top side toe contact