What burns out a charge coil/stator

[kitebuz]

Mine went out in 2010. After some intermittent rpm loss thru-out the season, I stopped getting spark in all cylinders. I replaced the stator, which gave me spark again, but i still had some intermittent rpm loss - 1,000rpm drop when running 4,000-5,000 rpm, but only after 20-30 minutes of operation. Once the rpm dropped, it would randomly jump back-up, run ok for a while, then drop back off. Pumping the primer bulb has no effect.

Started my motors last Sat in the driveway for the 1st time of the season. This one was a little rough start - seemed like one side didn't kick in for a little while, but it did after warming up and seemed to idle well.

Went to launch on Sunday, and it just would not start. Checked it today - & I don't have spark again. Checked the Charge Coil, & I was getting a low voltage off it - 65v vs the recommended >175v. Ohms were low too - 395 vs the spec of 480 (+/- 50).

I will get another charge coil on there & see if that gets my spark back.

Is there another part of the ignition system that could be faulty and burning out the charge coil? I put a used one on for the last repair, so maybe it was just on its way out as well.

I also tested compression today, which looked good. Cold #'s were: 105, 105, 95, 105.

 

[hidef]

Re: What burns out a charge coil/stator

Loose magnets in the flywheel could also cause issues. You need to follow the steps in the CDI guide for your model to isolate the issue.

 

[Jlawsen]

Re: What burns out a charge coil/stator

I more cases than not, its a bad ground. If the alternator (stator) doesn't see a load, voltage will spike. Intermittent ground loss is what yours sounds like and over time those voltage spikes are taking their toll.

It's important to realize that there really aren't any grounds (earth) on a boat. All of the negative connections rely on the difference in potential at the battery. The reason I'm say this is because a lot of folks blow past the battery side of the equation because they don't think it has anything to do with the ignition. It does.

 

[kitebuz]

Re: What burns out a charge coil/stator

Thank you - interesting points you both make.

I checked the magnets last year when I had the flywheel off. They seemed ok, but that was a physical test (not loose or missing). I was following my CDI test proceedure, but it is telling me something is wrong with my stator (again). You are right though - i should follow it thru till the end to see if it pinpoints any other issues.

Jlawsen - I think you make a good point: don't over look the simple things. Perhaps I am getting low readings b/c of a bad ground. I think I will start by going back thru and checking/cleaning my grounds. Boy, that would be a win!