replacing coils on Johnson 70 HP

[marcusknight]

I have a 1979 70 horse Johnson, Just curious if there are symptoms on when to replace coils. Sometimes I think the spark is not getting hot enough. The original coils are still being used.

 

[gm280]

If the coil is firing, it is "hot" enough. When you replace coils is when they stop sparking. If you can run the engine and pull one spark plug boot off and the engine changes sounds (RPM lowers) then that is a good coil and cylinder. Replace that spark plug boot again and do that with each cylinder to verify they all are firing and if so, you don't need new coils. Another issue would be if the coils are cracking or oozing anything out f them. If not, happy boating. JMHO

 

[racerone]

So " i think the spark is not hot enough "-----Testing is what you do and does the spark jump a gap of 7/16" or more with a spark tester ?-----What is the motor doing / not doing that leads you to believe there is a spark issue ??