I6 CDI Switchbox/Coil Durability? Design Flaw?

I don't want this to be interpreted as a slam against CDI. Everything I've heard about them has been positive. Every time I've dealt with them, they've gone above and beyond. They seem to know what they're doing. I'd still recommend them to anybody. I just have some questons about a couple things that concern me. I'd like to be proven wrong, actually.<br /><br />I'd like to start with a question - how many people are running a 2986 type ignition system from CDI? I'm talking about the switchbox and coil combo that replaces the Merc switchbox and original coil. How much use do you put on it, and how much higher RPM (3000 rpm and up) running do you do?<br /><br />I've recently encountered an incident where the coil onboard the 2986 unit shorted internally, causing spark to be too weak to make it to the plugs. Upon asking CDI about it, a technician told me that "about 1 in 200 coils" fail, and offered to send me another. They also told me that an ignition coil from a later model OMC coil would work. So I pulled my coil and noticed the potting compound had cracked. I took it to a local 'rude dealer and sure enough he recognized it as a very common Johnson/Evinrude coil. Upon looking the coil up, it turns out these coils are a COIL ON PLUG type of coil. I find it hard to believe that a single one of these coils would be very happy lighting off all 6 on a tower of power roaring away at 5 grand, when they were designed to fire one cylinder. Hmm.<br /><br />I did end up eventually frying this coil as well during the trip, though I had packed a spare purely for this reason. In all fairness, he sold me a used coil (I was outta time for a trip and he didn't have a new one). However, the failure occured almost exactly in the same amount of run time as my brand new CDI one. I don't think it's a coincidence. I currently have a new Johnson/Evinrude coil in place, and fear that my time is ticking every time I take it above idle.<br /><br />What do you guys think? How do I solve this problem? I've contemplated closing the gap between my rotor and cap terminals to where they almost rub to reduce the peak voltage the coil must fire at, but can't think of anything else to do. Anybody have any experiences to prove/disprove my theory? I would really love to hear about somebody using this system on an I6 and running WOT all day for an entire season with no problem, because that would give me hope.

Re: I6 CDI Switchbox/Coil Durability? Design Flaw?

I'm interested in seeing feed back on this . I have thought about going with this setup also.<br />Tim

Re: I6 CDI Switchbox/Coil Durability? Design Flaw?

79 Silverline<br /><br />Isn't this the type of ignition that was subject to failure if the battery voltage was too high or too low? Seems like I read that somewhere. Maybe that was the OEM version. Interesting subject.<br /><br />Dave..

Re: I6 CDI Switchbox/Coil Durability? Design Flaw?

What I've gathered from a few sources, is that if you use the wrong (read: cheap) type of battery, say a maintainance free car battery instead of a proper marine battery, the charging voltage can get too high, which usually causes the ignition system to cut out. I think I've seen figures saying anything lower than 9 volts or higher than 16 causes the switchbox to stop functioning correctly. I've read threads where people have disconnected their charging rectifier and their motors suddenly ran well, though mine never stopped running well until the coil fried.<br /><br />I am actually guilty of using a car battery, however, I think my charging voltage never exceeded 13 volts or so at anything I could rev to safely on the hose. I also think that it's not a maintainance free type battery either. I should go out on the water and run at WOT for awhile and see what my charging voltage gets to, because now I am rather curious. I'm not thinking that this is the problem though, as the boat runs perfectly until the the coil decides to die.

Re: I6 CDI Switchbox/Coil Durability? Design Flaw?

Over voltage is a regulator function ... the motor doesn't know (or care) what type of battery is there, only if there is one and it's operable.

Re: I6 CDI Switchbox/Coil Durability? Design Flaw?

We have used CDI products for many years and not had a failure, I beleive they are the best on the market and have a great support group. Gees this is starting to sound like a Amsoil pitch, sorry. I know if all that counted was outside looks that CDI or OMC would not make several differant coils fot the various engines I hope when you receive the right coil from CDI that it will correct your problem. I have never seen high voltage at the battery cause a problem with this system but any thing under 9 1/2 to 10 volts will destroy it. Clean all connections and make sure the switch box assm. is bonded to the the engine well, a extra ground wire would not hurt---good luck--Bob