1978 Johnson 175, 200, 235 HP Outboard Service Manual, Page 48Get this manual
2Do not pull on high tension leads at the ignition coil3Do not open or close any plug-in connectors while the engine is running4Do not set spark advance to other than specifications provided The test procedure steps provided in following pages, when used with troubleshooting step chart, will help in troubleshooting the systemBefore troubleshooting ignition system, bring 12 volt battery up to full chargeNEON TESTERS M-80 OR S-80 Check battery voltage in neon testers as follows:
1Set voltmeter on low volt scale
5Do not hold spark plug wires in your hand while checking for spark dischargesA severe electrical shock will resultUse insulated pliers designed for this purpose6Do not attempt any tests except those listed in the troubleshooting procedures
2Connect voltmeter ground to neon tester blue lead
7Do not connect an electric tachometer unless it is type which has been approved for use with this system8Do not connect this system to any voltage source other than which is specified
3Connect voltmeter red lead to neon tester black lead