74 JOHNSON 85 HP/ cracked coils, HELP

[WILDATRUPP]

All 4 coils are cracked and no fire at all, are these the culprit or could it be the powerpack? What made the coils crack? Any info. would be helpful and appreciated. Thanks

 

[billy4hp]

Re: 74 JOHNSON 85 HP/ cracked coils, HELP

All 4 coils are cracked and no fire at all, are these the culprit or could it be the powerpack? What made the coils crack? Any info. would be helpful and appreciated. Thanks

Are the coils original or have they been replaced?

To test the coils you can use an ohm meter to see if the primary winding circuit is open (bad) or complete (possibly good). If they are cracked bad enough the voltage fires through the crack rather than through the spark plug wire, electricity always takes the path of least resistance...

As to what made them crack, if they are original I would say you got the service life out of them and a little extra being a 1974....

Good luck,

Billy

 

[ezeke]

Re: 74 JOHNSON 85 HP/ cracked coils, HELP

When no spark is seen on any cylinder, the first test is to disconnect the black and yellow kill wire from the powerpack.

As a general rule, when ignition coils are cracked, discolored, melted, or otherwise damaged, they should be replaced. A bad ignition coil on your system can kill the powerpack so it isn't worth the risk.

Ignition coils can test good over a range while failing when heated up.

On your motor, it is extremely important that the ignition coils are solidly grounded to the mounting rack, and that the mounting rack's grounding straps are in good shape and solidly grounded.