78 johnson Spark-Ignition system !Pics Added! troubleshoot help needed

[mmawonder]

Well my 25 hp 1978 johnson seahorse 25R78C is not starting, after cleaning, adjusting and rebuilding the carb, it made a couple attempts to start but thats about it. I just pulled the spark plugs out and grounded them to the case and pulled the cord and I have no spark on both spark plugs. Then I took the coils off and cleaned and sanded the contact points. Then I took the flywheel off to see if I can service the points, but to my suprise there are no points, there are 2 little plastic boxes that looks like electronic ignition. What should i do now, is there a way to test or service that ignition system? How can I locate the problem? I dont mind replacing most of the ignition system, if it is going to give me a nice hot spark.

 

[o/b tech]

Re: 78 johnson Ignition system troubleshoot help needed

Re: 78 johnson Ignition system troubleshoot help needed

First try disconnecting the push button shorting switch and check for spark again.

 

[mmawonder]

Re: 78 johnson Ignition system troubleshoot help needed

Re: 78 johnson Ignition system troubleshoot help needed

i just pulled the cap off and the shorting switch seems to be fine

 

[o/b tech]

Re: 78 johnson Ignition system troubleshoot help needed

Re: 78 johnson Ignition system troubleshoot help needed

The switch should be a sealed unit and clean inside. Try taking off the ground wire at the powerhead. Also check to make sure that the pack has a good ground and see if this helps.

 

[mmawonder]

Re: 78 johnson Ignition system troubleshoot help needed

Re: 78 johnson Ignition system troubleshoot help needed

I broke the plastic housing while taking the switch off, it was clean on the inside, the gorund wire seems to be going to a screw that holds one of the coils not to the power pack. The other wire however runs to the power pack i think. Here I took 2 pictures of the system. How can I test these components such as the two plastic boxes, coils and the power pack?

Top view under the flywheel

side view where the coils are

 

[mmawonder]

Re: 78 johnson Spark-Ignition system !Pics Added! troubleshoot help needed

^^^

 

[dodgeramsst2003]

Re: 78 johnson Spark-Ignition system !Pics Added! troubleshoot help needed

Well I'm not 100% on these ignition systems, but if I remember right, the parts under the flywheel are just magnetic pickups. Its usually the powerpack that goes. I had my 78 15hp quit running while trolling last year. I took a chance and replaced the powerpack and its been running like a top since.

 

[mmawonder]

Re: 78 johnson Spark-Ignition system !Pics Added! troubleshoot help needed

Is there a way I can test the power pack before I order one?


Ps: I found this one for $76 delivered and they claim it to be better than original

http://www.outboardignition.com/jandesearch.asp?cat=itemname&cval=4&hval=16&val=6
or I can get the sierra from iboats for $65 delivered http://www.iboats.com/mall/partfind...gd_poid=112893&gd_row=52&**********=089961411

 

[mmawonder]

Re: 78 johnson Spark-Ignition system !Pics Added! troubleshoot help needed

Well I solved my issue and thought I would update this thread. My problem was the wire that grounds the power pack was cut in half. I am assuming from rubbing on and off to the cover. I cleaned and reconnected the cable using butt connectors and now I have spark like I neved had before. When I do a spark testing you can hear the plugs clicking from 3 feet away. Anyhow, now my motor starts well and runs strong, I guess until something else fails.