Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 50Get this manual
IGNITION SYSTEM
BRESISTANCE TEST 1Use an ohmmeter to perform the following pri mary winding test0.02-0.38Q
2Use an ohmmeter to perform th followi ng secondary winding testNOTE: High tension cables must have spark plug cap removed before testingCap contains 5k ohm resistor
IMPORTANT: To remove spark plug cap from high tension leads, turn cap counterclockwise while applying slight outward pressure00 NOT PULL HARD or lead may be damagedTo install cap, turn cap clockwise threading cap onto high tension lead