2004 SR Johnson 2-stroke 40, 50HP Service Manual, Page 254Get this manual
GEARCASE DRIVESHAFT SHIMMING Position Shim Gauge Bar, PIN 334984, from Driveshaft Shim Kit, PIN 433032, against guide pins of the tool baseCheck the squareness of the pinion to the driveshaft by holding the shim gauge bar against the bearing housing (between the screw holes) while rotating just the driveshaft and pinion assembly and measuring the clearance between the shim gauge bar and the pinion Replace the pinion or the driveshaft, as necessary, and repeat the check if variance exceeds 0.002 in(0.050 mm)
1Position shim gauge 2Tool base
Check the squareness of the bearing housing mounting surface by holding the shim gauge bar against the pinion while rotating just the bearing housing and measuring the clearance between the gauge bar and the bearing housing with feeler gaugesMeasure between each pair of screw holesReplace the bearing housing and repeat check if variance exceeds 0.004 in(0.010 mm)