2005 Seadoo Islandia Engine

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I recently Purchased a 2005 Seadoo Islandia 250 DFI, the previous owner stated everything is good and is water ready. I brought it home to find out its not. Misfiring horribly amongst my issues. I had someone come out to look at it and said so far Cylinder 1 has spark and fuel but nothing else and might be a dead cylinder. I am going to have a compression test done soon but for now I am assuming engine is toast. I am in Orlando, FL I was wondering if anyone has had similar issues or has had to replace or rebuild engine and can give me any further advice? I know the engine is a 2005 Mercury 250DFI Thanks in Advance everyone!