2006 Johnson SD 30 HP 4 Stroke Outboards Service Manual, PN 5006592, Page 224Get this manual
GEARCASE SHIMMING AND GEAR BACKLASH CHECKS Thread the sliding hammer onto the propeller shaft and strike few gentle outward taps
Checking the Propeller Shaft Thrust Play
After adjusting all gear positions, measure the propeller shaft thrust play
IMPORTANT: Maintain the forward gear thrust washer at the standard thicknessAdjust only the reverse gear thrust washerInstall gear adjusting gauge to the propeller shaftPush the propeller shaft inwardHold the shaft in and set the dial gauge to zeroSlowly pull the propeller shaft outwardRecord the maximum gauge readingThe actual propeller shaft thrust play should be 0.008 to 0.016 in(0.20 to 0.40 mm) If the measurement is greater than the specification, increase the thickness of the reverse gear thrust washer If the measurement is less than the specification, decrease the thickness of the reverse gear thrust washer