1971 Johnson 40HP outboards Service Manual, Page 66Get this manual
DESCRIPTION The 40 HP Electric starting Model electrical system is made up of the ignition system, the starter system, and the storage batterySee Figure 7-1, Electrical System Schematic at end of this sectionThe starter solenoid and motor cable connector are located in the lower motor coverSee Figure 7-2TROUBLESHOOTING THE ELECTRICAL SYSTEM Trouble in the electrical system often is first evidenced by failure of the starter to operate, and may be caused by failure of anyone or more of the components covered in this sectionA large percentage of electrical circuit as well as component failures
are caused by loose or dirty electrical wlrmg connectionsStarter system troubleshooting is included in the Trouble Check Chart in Section 2Servicing of the starter solenoid and starter, and battery maintenance, are covered in this Section
BATTERY SPECIFICATIONS
For best performance, we recommend 12-volt, 60 ampere hour battery, or better, with minimum of minutes cold starting capacity at 300 amperes discharge, zero degrees Fahrenheit, and 10 second voltage reading of 7.5 volts