Johnson Evinrude Outboard Motors 1956-1970 1.5-40hp repair manual., Page 162Get this manual
IGNITION
The needle should swing upscaleIf the needle swings downscale, the polarity is reversed2- If voltmeter is not available, pencil may be used in the following manner: Disconnect spark plug wire and hold the metal connector at the end of the cable about 14" from the spark plug terminalNow, insert an ordinary pencil tip between the terminal and the connectorCrank the engine with the ignition switch ONIf the spark feathers on the plug side and has slight orange tinge, the polarity is correctIf the spark feathers on the cable connector side, the polarity is reversed3- The firing end of used spark plug can give clue to coil polarityIf the ground electrode is "dished", it may mean polarity is reversed5-4 WIRING HARNESS