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  1. #1
    Member
    Join Date
    Jul 2013
    Location
    Richland, WA
    Posts
    614

    Optimax ECU Compatibility

    2003 Mercury 250XS, serial number OT652929

    Built by Mercury Racing with the lower rev limit and high octane fuel. Am I limited to only the 2003-2005 250XS's for buying a used ECU or are there other models/years that will also work?

    Thanks
    John Wolff
    2003 Allison XB21 2+2
    2003 Mercury 250xs

  2. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #2
    You are better off having your original ECU modified to fit your need than trying ECU's from different years. There are other parameters within the ECU that could have also been changed (such as fuel curve) that could be detrimental to your powerhead.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."