Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 53Get this manual
IGNITION SYSTEM
CPOWER TESTOPTIONAL IMPORTANT: model 9800 Merc-o-tronic Magneto Analyzer (91-76032) with coil selector switch set on "CDI" must be used for test thru E1Connect magneto analyzer test leads to ignition coil
aBlack Analyzer Test LeadsConnected to Ignition Coil GroundRed Analyzer Test LeadConnected to Spade Connector of Ignition CoilLarge Red Analyzer Test LeadConnected to High Tension Spark Plug Lead (Wire Spring Inside Spark Plug Boot) 2Turn "Hi-Lo" current control knob all the way left past "Lo" position3Set analyzer to position "Coil Power Test 4Slowly turn current control knob clockwise while noting current value on scale 15When current value reaches 1.7 to 2.1 amperes, stop turning current control knob and note mm spark gap; it should be firing steadily6If spark is faint, intermittent or no spark occurs at 2.1 amperes, replace ignition coil7If ignition coil checks out OK, proceed to Test "High Speed Test DHIGH SPEED TESTOPTIONAL