I have a 150 hp 2 stroke that I have done everything under the sun to fix the symptom it's have. Starts fine, gets on plane fine, mid range fine but fails to reach wot 90% of the time. New fuel lines, filter, fuel pumps, cleaned and rebuilt carbs and new spark plugs. No water in gas and use non-ethanolmost the time. It's almost like it's off a cylinder only achieving 4800-5000 rpm when it should be around 5500-5600. At times it does open up all the way and when it doesn't it sounds like it's trying to with a jumpy tachometer. I noticed the spark plugs have normal fouling but one is fouled like the others. Is it possibly a coil pack?