Troubleshooting no spark on a 91 Johnson 60

hypeshipe

Seaman Apprentice
Joined
May 16, 2011
Messages
41
Please respond to my following readings. I am using the following guidelines to troubleshoot my problem: (my comments are in Red

first, rule out the kill circuit by disconnecting the black/yellow kill wire from the powerpack and repeating your spark test. Best to have all spark plug wires disconnected for this test (but grounded to the engine block to avoid damage to the powerpack), cause if the engine starts, the only way to shut it off is to flood it with the primer (choke).I disconnected the black/yellow wire and still did not start.

If you get spark, then the black/yellow wire has a short to ground somewhere between the powerpack and the keyswitch, or the keyswitch is faulty (the two "M" terminals should test positive for continuity with key "off", and open otherwise) I have continuity, or the emergency kill switch is shorted (should be open to run, closed to kill) I disconnected this switch and still did not start.

Still no spark, disconnect yellow wires from the stator to the rectifier and retest. If the ignition now fires, replace the rectifierDisconnect and did not start.

Check the stator resistance. You should read approximately 500 ohms from the brown wire to the brown/yellow wireResistence =392.

Check the DVA (peak AC) output from the stator while cranking. You should have a reading of at least 150V or more from the brown wire to the brown/yellow wire (while connected to the pack). Any less means faulty statorI have not done this.

Check the cranking RPM. A cranking speed of less than 250-RPM will not allow the system to fire properlyI have not done this.

Check the timer base resistance from the white wire to the blue, green and purple wires. Reading should be 38- 42 ohms. Any other reading means faulty timer baseThese wires were consistently reading 12 (the test results of another motor in the link in the second post of this thread leads me to believe the 40 +- 2 ohms is not an accurate spec.)

Check the DVA output from the timer base. A reading of at least 0.5V or more from the white wire to the blue, green and purple wires (while connected to the pack) is needed to fire the pack. Any less means faulty timer baseI have not done this due to needing to cut into harness.

Timer base and stator check out, your powerpack is bad.
 
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hypeshipe

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Joined
May 16, 2011
Messages
41
Re: Troubleshooting no spark on a 91 Johnson 60

I found a guy that had similiar timer base and stator readings here---> http://forums.iboats.com/showthread.php?t=289125&page=1

It turned out that his rectifier was bad. Could these readings indicate a bad rectifier? I disconnected the yellow wires from the stator to the rectifier and it still did not start. (now that i think about it i disconnected the yellow and yellow/gray wires too)
 

hypeshipe

Seaman Apprentice
Joined
May 16, 2011
Messages
41
Re: Troubleshooting no spark on a 91 Johnson 60

Well, despite an obvious lack of interest in my thread, I will continue to post update on the diagnosis of this problem. (Hopefully someone will chime in to help coach me through this).
 

hypeshipe

Seaman Apprentice
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May 16, 2011
Messages
41
Re: Troubleshooting no spark on a 91 Johnson 60

I just ruled out my rectifier by checking continuity. It only shows continuity one way meaning it is working.
 

hypeshipe

Seaman Apprentice
Joined
May 16, 2011
Messages
41
Re: Troubleshooting no spark on a 91 Johnson 60

When I put the recitifier back in I check the spark and had it on all cylinders. It then started right up. I now have no idea if it was a connection problem or if it is intermitant and is going to leave me stranded.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Troubleshooting no spark on a 91 Johnson 60

Your motor should run just fine without a rectifier at all. The only thing it should affect would be the charging system. I'm betting you indirectly cleaned up a bad connection somewhere...
 
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