Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 448Get this manual
Reverse Gear Backlash CHECKING Reverse Gear Backlash Specification: 0.040-0.060 in(1.01 mm-1.S mm)NOTE: If the bearing preload tool has not already been set up see "Drive ShaftBearing Preload Tool", 'Installation' section firstNOTE: The reverse gear bearing adaptor installation tool is used to apply light preload to the reverse gear in the following steps
2Install dial indicator as shown in the following figure
1Install the reverse gear bearing adaptor installation tool into the gear housing to hold the reverse gear against the thrust bearing as follows: aAssemble the reverse gear bearing adaptor installation tool into the gear housing and tighten it by hand until slight resistance is feltbTorque the adaptor's driver bolt to 45 lbin(5.0 Nm)a g
70717 Nuts (4) (obtain locally) Threaded Rod [38 in(9 .5 mm) obtain locally] Dial Indicator Holding Tool (91-89897) Dial Indicator (91-58222A1) Indicator Pointer Backlash Indicator Rod (91-53459) (for 1.64: or 1.75: 1) Backlash Indicator Rod (91-78473) (for 1.87: 1)