Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 242Get this manual
Pinion Gear and Drive Shaft IMPORTANT: If Initial inspection determines that drive shaftpinion gear and gearcase MAY BE returned to service, it Is recommended that aligning reference marks be made on the drive shaft [approximately 41n (101 .6mm) above water pump keyway] and pinion gear
Remove drive shalt from gear housing using either method following: Install Drive Shaft Removal Tool (9 1-92785Al )on drive shaftHit tool with hammer to remove shaft from housing
with crayon prior to their removalThese marks, when aligned with fixed point (I.Edowel pin, bolt hole, etc will provide constant reference point to eliminate runout variance in the pinion geardrive shaft when checking pinion heightREMOVAL