Tohatsu 4 Stroke MFS 2/2.5/3.5A Outboards Service Manual, Page 47Get this manual
Maintenance 11) Inspection of Spark Plug
1Remove plug cap and then spark plugUse spark plug cleaner or wire brush to clean spark plug electrode 1Replace if necessaryCheck electrode for corrosion or excessive build up of carbon, and washer for damageReplace if necessaryCheck spark plug gap aReplace if the gap is over specified valueAdjust gap if it is out of specified rangeSpark Plug GapStandard 0.80.9 mm (0.031- 0.035 in) Functional Limit1.0 mm (0.039 in)