Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 14Get this manual
MAINTENANCE
Inspection and Maintenance Schedule
Before Each Use
1Check engine oil level2Visually inspect the fuel system for deterioration or leaks3Check outboard for tightness on transom4Check propeller blades for damage
After Each Use
1Flush out the outboard cooling system if operating in salt or polluted water2Wash off all salt deposits and flush out the exhaust outlet of the propeller and gear case with fresh water if operating in salt water
Every 100 Hours of Use or Once Yearly, Whichever Occurs First