Testing a coil and CDI Box?

[shane-r13]

I have a 1978 Artic Spirit 20HP (Basically a Suzuki before Suzuki was sold in the US). I have no spark. It has happened before and I removed the killswitch and all was well. Go to test it in the barrel before packing it for a trip this week and now no spark. I think I tested the coil right but I’m not sure. I also did a OHM test on the CDI but I don’t know what I’m looking for.

Also maybe if these have failed any leads on replacements? eBay prices scare me, they want more than I paid for the motor haha.

Shane

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[shane-r13]

Ok so when i tested the coil, i put my multi in to Ohm’s, when i put the leads into the ends of each plug wire, i got a reading. when i put them into the plug wire and touched eother the ground or the one where power comes into the coil i got nothing. when i touched the power tab and ground tab i got a ready as well.

i also hooked my meter up to the incoming ground and power from the CDI and i got somewhere in the neighbourhood of like 150volts while cranking. I know this isnt the correct way as you need a DVA i believe to test it properly but i wanted to see if i was even getting any power from my CDI to the coil.

Still lost though as to the true issue.

[jerry-ahrens]

It will be hard to get an accurate reading of the CDI box (or whatever Suzuki called it) without a peak reading volt meter. CdI Electronics sells an adaptor that allows you to use a standard VOM meter. Your other hurdle is knowing how to test the system. I’m sure there is some sort of sensor coil under the flywheel, as well as an ignition box and coils… CdI does not show any troubleshooting instructions on their website for that motor. You may want to call them anyway and ask? They are friendly to talk to.

[shane-r13]

Thanks for the reply, I’ve
Looked at the CDI site and yes as you pointed out no instructions for my motor or Suzuki period. This electronics is a PITA, I miss my points and condensers.

[frankr]

From the limited amount of information you have given. I would say your coil and CDI are ok. I’m kind of surprised you could have those readings and no spark. The fact that you are getting some kind of reading from the CDI would indicate that it and the charge coil and sensor are working to some extent. Furthermore you said the problem occured before and healed itself. When this stuff goes bad, it stays bad. I would be looking for something that is intermittent, such as loose or broken wires, cranking speed, etc.ect.

[shane-r13]

quote FrankR:

From the limited amount of information you have given. I would say your coil and CDI are ok. I’m kind of surprised you could have those readings and no spark. The fact that you are getting some kind of reading from the CDI would indicate that it and the charge coil and sensor are working to some extent. Furthermore you said the problem occured before and healed itself. When this stuff goes bad, it stays bad. I would be looking for something that is intermittent, such as loose or broken wires, cranking speed, etc.ect.

Is there any else i can provide that will help diagnose? This is my first time dealing with electronic ignitions so my knowledge is limited. Did i test my coil right? I have no manual and cant find one online for the exact readings for my coil etc, but honestly my thoughts were similar to yours that it "fixed" it self before so maybe shorting to ground. Unfortunately i have tightened all connections, took the wraps off the harnesses and see no loose wires or any type of short. Thats what led me to believe it was a bigger issue. Also worth noting I am unable to remove the flywheel to look under it. I can’t get it off and don’t have the proper puller. But you can see through multiples holes and just from looking it is CLEAN, like no corrosion or anything. While that doesn’t generally mean much I take it as a positive sign.

I’m going to head out soon as its not to early to annoy the neighbours with a cranking engine and give it another go. Leave for my trip Wednesday and would like to use this motor not my 9.9.

Shane

[frankr]

Not knowing anything about this particular system, and going strictly by your test results on the coil, I would say the coil has a single secondary winding, with a plug wire coming off each end of the coil. That means that BOTH plugs fire at the same instant, and the electricity comes off one end of the coil, jumps one plug gap, travels through the block to the other plug, and jumps that gap, and back to the coil. So, you have to have a spark gap set up off both plugs wires when checking for spark. In other words, you can’t check for spark one plug at a time.

Assuming that’s the way the coil is constructed, that is.

[shane-r13]

Would leaving one plug in the block and connected and the attaching my spark gap tester to the other be the right way to check for spark on this?

Thanks

[shane-r13]

Does these photos of the coil help?

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[frankr]

quote Shane.R13:

Would leaving one plug in the block and connected and the attaching my spark gap tester to the other be the right way to check for spark on this?

Thanks

That ought to work. Another way is use two spark gap testers. Another way is ground one plug wire. What won’t work is leave one plug wire disconnected and dangling in air.

BTW, the kind of coil I am describing is not at all unusual. It is what is on my Honda motorcycle. It is also what is used on many antique opposed twin outboards. Nothing new under the sun, they say.

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