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  1. #1

    1997 GTX MPEM Question

    I recently purchased an aftermarket Arieltek MPEM for my 1997 SeaDoo GTX, at a savings of over $750 CDN funds, over and above the Bombardier unit. The 5 amp was blowing . Did all the diagnostics that I could based on info from the net. I am not that technical. Plugged the new MPEM in and the machine fired right up, in the driveway. Only function lost, and I was made aware of it up front, is that the DESS function is now disabled and the machine will start with any key. Have yet to put in the water.

    Question 1:

    The manual for the new MPEM says that it is programmed to operate hand in hand with the
    engine timing set to -4 degrees (based on the #8 stamping designation on block beside serial number plate) whereas my engine is
    currently set at -1 degrees (based on the #5 stamping designation on my block).
    Will this cause a problem / cause damage to my machine, if I do not have the timing adjusted? If no damage per se,
    with the timing off / retarded by 3 degrees too much, from a performance
    view point, would this effect either the "out of the hole" or "top end"

    Question 2:

    The engine now idles @ 3000 r.p.m. Will this be a problem or should I wait to see what r.p.m. is with machine in water? And if still @ 3000, should it be adjusted down and if so, to what r.p.m.?

    Any and all help would be greatly appreciated!

  2. #2
    Waterluvr's Avatar
    Join Date
    Mar 2015
    Northern Indiana
    Welcome to GH Holt!

    The Arieltek MPEM's have a button to adjust the timing curve on them, set it in accordance with the service manual guidelines to the mark stamped into the engine case next to the engine ID tag just above the pto.

    3K rpm is just about perfect for the '97 GTX, it really boils down to personal preference and the weight of the primary rider a bigger guy want's it set to 3K and a smaller person maybe tweak it down to 2800 or so.

    Don't throw your old module away, they can be repaired for the 5 amp fuse issue I just did a thread here in the ECU section that shows how it's done. You can read that here:

    Here's where the faulty diode is located in the MPEM for your 1997 GTX, the red arrow is pointing to it on the x-ray:

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  4. #3
    great thread, w.l....but, hth did you remove the potting?

  5. #4
    Waterluvr's Avatar
    Join Date
    Mar 2015
    Northern Indiana
    Quote Originally Posted by timmyboy76 View Post
    great thread, w.l....but, hth did you remove the potting?
    Very carefully! I replied in more detail to your question in the original MPEM repair thread in the above link, but I'll copy and paste it here as many people might not make there way over to the ECU support forum:

    ~Like everything else I'd never done (neither had anyone else I knew at the time) there was a learning curve with some trial and error when I first started repairing these for customers. My first few go arounds were with the older style wired MPEM's where the correct side of the module to gain access was exposed to just the rubberized potting and a heat gun and hobby knife worked ok for those.

    On the newer style modules like the rfi, you have to get through the hard outer plastic shell just to chip away at the potting, and I use a dremel tool dialed way down on the speed setting with a small thin carbide bit that tile mason's use to cut out existing grout joints to make a square cut into the plastic and open a window to the potting compound.

    The engraver's bit that comes with most dremel style tools works pretty well to open the plastic up, just doesn't last very long and dulls quickly but would be fine for a one time use scenario.

    I make the four straight lines with the cutter just deep enough to get through the plastic shell, stop and heat it up with the gun and gently pry the plastic up and off exposing the potting.

    From there, I use a hobby knife and small flat blade pocket screwdriver with the tip occasionally run through the flame of a mapp gas torch and those tools peel away the potting without much resistance and you just need to take your time and be patient not to dig too far in or damage any other components the diode is the largest thing in that general area.

    I usually start with the knife and make a shallow cut straight down into the potting along the edges of where the plastic was removed and the flat blade heated screwdriver tip to dig down and remove most of the potting. What you want to avoid when doing one of these is using a heat gun to much as it's possible to generate so much heat in that rubber potting over a wide area of the module it will short the copper circuit legs on the board that carry power and grounds that run alongside each other there's no fixing one if that happens.

  6. #5
    Thank You for the great info. Yes, my Arieltek module does have a white button on it and in reading the instructions that came with it, I guess I didn't quite understand what I was reading hand in hand with adjusting the timing curve. I will have another look this evening and if further questions, get back to you. I will also P.M. you. Thanks!!

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