Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 441Get this manual
LEFT HAND NON-RATCHETING
NOTE: Bearing Preload Tool (91-14311A1) should remain installed on driveshaft after setting pinion gear depth as it is required to properly check forward gear and reverse gear backlash
Reverse Gear
DETERMINING REVERSE GEAR BACKLASH
NOTE: Reverse gear backlash is adjustable using shims; it can be checked as follows:
1Install Driver Tool (91-18605) into reverse gear assembly2Slide Pilot Ring (91-18603) over driver tool and seat pilot ring against inner ledge in gear case3Thread Retainer (91-18604) into gear case cover nut threads4Torque Screw (91-18602) to 45 Ibin(5 Nm) against driver tool