2005 Mercury 90elpto 4s 4 stroke running rough

bruno19

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Joined
May 6, 2014
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Hello, I have a 2005 Mercury 90 elpto 4s 4 stroke. it is only running on 2 cylinders. The top and bottom cylinders are firing. I can remove the middle two plug wires with no change in motor performance. I have cleaned the carbs, changed fuel filter, replaced spark plugs, and even changed the cdi module. I am at my breaking point here. Any help would be much appreciated! thank you.
 
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