2006 Johnson SD 30 HP 4 Stroke Outboards Service Manual, PN 5006592, Page 205Get this manual
GEARCASE WATER PUMP
WATER PUMP
Disassembly
Remove the gearcase from the exhaust housingRefer to "REMOVAL AND INSTALLATION" on page 201 Loosen four (4) nuts and the washers, then remove the impeller housing
Inspection
Check the impeller for overheating, hub separation, and visible signs of wear or damageCheck the plate and inside the housing for scoring, distortion, and impeller material transferCheck the housing for cracks or melting