Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 444Get this manual
LEFT HAND NON-RATCHETING
7Tighten nut to 45 lbin(5 Nm)This will seat the forward gear against the forward thrust bearing and tends to hold the propeller shaft from moving when measuring backlash
NOTE: Bearing Preload Tool (91-44307A1) should still be installed from having previously been used to determine pinion gear depth and reverse gear backlashIf it is not still installed on gear case, refer to "DETERMINING PINION GEAR DEPTH," previously, for proper installation procedure8With the proper preload applied to the propeller shaft and the driveshaft, rotate the driveshaft clockwise to 10 complete revolutionsThis will seat the forward gear and upper driveshaft bearings and thus provide the most accurate backlash readings9If not previously installed: aThread stud adaptor [from bearing preload tool (91-44307A1)] all the way onto studbInstall: Backlash Indicator Tool (91-78473) Dial Indicator Holder (91-89897) Dial Indicator (91-58222A1) 10Position dial indicator pointer on line marked "1" on BACKLASH INDICATOR TOOL, if gear ratio is 1.87:1 (15 teeth on pinion gear), or on line marked "2" on BACKLASH INDICATOR TOOL, if gear ratio is 2:1 (14 teeth on pinion gear)