2003 Johnson ST 55 HP WRL 2 Stroke Commercial Service Manual, PN 5005483, Page 81Get this manual
IGNITION SYSTEM TESTS Ohmmeter Ground Test To test for grounded condition, connect ohmmeter, alternately, between terminals "8" and "C" and clean engine ground Any needle movement indicates sensor coil or leads are grounded Locate and repair ground, or replace sensor coilconnect meter black lead to ground tab on the coilConnect ohmmeter red lead to coil primary terminal Meter must show 0.1 0.05 ohms
Connect ohmmeter red lead to coil primary terminalConnect ohmmeter black lead to coil spark plug terminal Meter must show 275 50 ohmsComplete all circuits disconnected during this test
Ignition Coil Tests
To avoid personal injury from electrical shock, perform all coil tests on wooden (or insulated) bench top