Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 121Get this manual

Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 121

CYLINDER HEAD
Cleaning and Inspection
Cylinder Head
1Inspect the cylinder head for mineral deposit blockagecorrosion in the water passage ways, clean any depositscorrosion observed2Inspect the cylinder head for carbon deposits In combustion chamber (use round scraper to clean away deposits)Be careful not to scratch or remove material