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  1. #1

    I need some info on 787 timing/cdi

    I have come across a problem that has me stumped. I have had this 1997 spx for 5 years and it has always ran well. Here is the short story, It is taking working mpems and making them totally responsive so the ski will not recognize a key or do anything when I press start button. Obviously this is a very difficult and expensive problem to diagnose. I would like to bypass the mpem. My problem is I cannot find a cdi (or icm) for these engines that works independent of the mpem.

    Long story So it started up by occasionally I would press the start buttton and nothing would happen, press it again and where good. This progresses over maybe 20 rides and two weeks to the point it is at now. Basically it acts as i there is no battery in the ski nothing responds. However I am getting power to the electric boxes and starter and they all have good grounds. I tested all the various potential culprits which all checked out so I replaced the mpem. This ski is a 97 spx so it has the separate cdi and mpem which proved to be very hard to find so I ended up swapping out the entire front electrical box with a 96xp box. I was told this was a kosher thing to do from a very respectable and knowledgeable sea doo mechanic and from my study of the wiring diagram i concluded it would work just fine. It did work just fine . . at first. However it ended up doing the same thing as the previous mpem, meaning there is another culprit aside from what is in the front electrical box as that was all new. I am assuming this is some sort of messed up wiring or something but i do not want to afford diagnosing that as the price of the mpems taking a shit adds up quickly.

    Right now its either part it out or find a cdi unit that has an integral timing curve so i could wire up the ski to run without the mpem. I am certain this can be done but from what i understand the cdi gets its timing curve from the mpem. Does anyone know of a product that i could come by at a reasonable price that would accomplish the whole timing thing independent of the mpem?

  2. #2
    water worx's Avatar
    Join Date
    Aug 2006
    Sunny Fla,Ft Pierce
    Replace the start/stop switch.

  3. #3
    the start stop switch is capable of causing an electrical failure in the mpem? IE ruins one mpem, new mpem works for 10 times then stops altogether and is now unresponsive.

  4. #4
    water worx's Avatar
    Join Date
    Aug 2006
    Sunny Fla,Ft Pierce
    The switch is a on/off switch if its not working properly can cause the mpem to do weird things.

    To answer your other question...You can wire a MSD enhancer to work without a mpem.

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