2004 SR Johnson 2 Stroke 9.9, 15, 25, 30 HP Outboards Service Manual, Page 64Get this manual
MAINTENANCE COOLING SYSTEM
COOLING SYSTEM
Check the condition of cooling system components regularlyThe outboard cooling system consists of: water intake screens; overboard water pressure indicator; water pump; all internal water passages; thermostats; and all external water hoses and fittings
9.915 MODELS
Remove the plug from the flushing port on exhaust manifold
Flushing
Flush the outboard with fresh water following each use in brackish, salt, or polluted water to minimize the accumulation of scale and silt deposits in cooling system passagesThe outboard can be flushed on the trailer or at dockside; running or not runningInstall flushing adapter and garden hose