Mercury 50 hp rough running over 3200 rpm

[boatman2014]

I have a 2002 Mercury 50 hp 3cyl model # ELPTO engine starts fine idles good, runs fine Until you try and go over 3200 rpms then engine starts to shake and rattle like motors is coming apart. Any suggestions on what to check first. Have checked plugs and fuel, fuel filter those all seem to be ok.
Thanks

 

[Nathan Bond]

When you say you checked the plugs, did you just look at the plugs or did you check for spark?