1978 Johnson 4HP outboards Service Manual, Page 41Get this manual
cInsert jumper wire between the "A" minals of both four wire connectorsSee Figure 4-22dInsert jumper wire between the "0" terminals of both four wire connectorsSee Figure 4-22 hCrank the engine with the starter rope and tap load button "8 When load button "8" is pressed, spark should jump at the gap of the spark tester connected to No2 ignition coil onlySee Figure 4-22If spark occurs at both gaps of the spark tester during this test, replace the power packiReverse the jumper wires on terminals "8" andC" in the power pack end of the four wire connector, and repeat step hto fire No.1 ignition coilIf spark occured during each "trigger input test," the sensor coil is defectiveIf there was no spark, or spark occured on one "trigger input test" but not the other, continue the troubleshooting procedure
Ii+SAFETY WARNING
To avoid possible shock hazards, do not touch the terminal ends of the jumper wires while making connections to the power pack, or when cranking the engineeAttach jumper wire to the blue lead of the neon tester, then insert the jumper wire to terminal "8" in the power pack endof the four wire connectorSee Figure 4-22fConnect jumper wire to the positive (+) side ofthe battery adapter, (on M-90 neon testers, connect the jumper wire directly to the black lead of the tester), and insert the jumper wire to terminal "C" in the power pack end of the four wire connectorsSee Figure 4-22