1991 Johnson/Evinrude EI 60 thru 70 outboards Service Manual, Page 298Get this manual
Motor Test, No Load
Securely fasten motor in suitable fixture before proceeding with this test
1Use battery rated at 360 cold cranking amps (72 amp hrs or higher that is in good condition and fully charged to perform this test2Connect 0-50 amp ammeter in series with the battery's terminal, ammeter RED lead toward terminal
3Attach or hold vibration or mechanical tachometer to the motor while performing this test4Monitor motor RPM and current drawRefer to the chart below for the correct specifications for your motor