2003 Mercury 150 XL Saltwater

[binspector]

My 2003 Mercury 150 XL Saltwater has a high speed miss. I have removed and cleaned all three carburetors and I have replaced fuel lines, filter, and water seperator. I have also replaced the spark plugs but it still has the same miss. The boat idles fine and has plenty of power. It runs perfect up to about 4000 RPM. Once I open the throttle and it goes past 4000 RPM it develops a small miss. It does not effect the speed of the boat however you can feel it and hear it in the engine. Once I reduce the throttle to 3900 RPM or there about, it smooths out and runs fine again. I have been told by some people that it could be a bad stator but I know nothing about this. Is there any way to test the stator or the coils or should I just break down and take it in to the shop? Any suggestions?