Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 257Get this manual
12If backlash is LESS than specified, LARGER shim should be usedIf backlash is GREATER than specified, SMALLER shim should be usedNOTE: By adding or subtracting .001 in (0.025mm) shim, the backlash will change approximately .0015 in (O.038mm)NOTE: If the variation in backlash between readings exceeds .005 in(0.13mm), the pinion gear may be not seated correctly and should be checked with the feeler gauge and Pinion Location Tool (9 1-56048)13If forward gear backlash is within specifications, then Bearing Preload Tool, Backlash Indicator ToolPVC pipe, forward gear assembly, bearing adaptor, bearing carrier and propeller shaft can all be removed from the gear caseDETERMINING LOWER TAPERED ROLLER BEARING SHIM REQUIREMENTS IMPORTANT: Pinion depth and forward gear backlash MUST BE DETERMINED BEFORE setting drive shaft lower tapered roller bearing shim height1Install Drive shaft Removal Tool (9 1-92785A 1) on drive shaltPosition dial indicator so that indicator arm touches bottom of drive shaft removal toolTotal up and down movement of drive shaft should bE .002 in- .006 in(.051mm.l S2mm) indicaledon dia indicatorIf, for example, total movement of drive shat is indicated as .050 in(1 .27mm), the sum left.046 in (l .17mm) would the amount of shims placed undel lower tapered roller bearing race 3To install shims, remove dial indicator assembly frorr gearcase4Install drive shaft Holding Tool (91-12362) over crankshaft end of drive shaft5678Use socket and flex handle to hold pinion nut (pad area where flex handle will contact gear housing)Remove pinion nut and washer from pinion gear while rotating drive shaftRemove pinion gear from gear housingUse Collar Tool (91-93227) to remove drive shaft collar from housing