Motor shut off at full rpm

I have a ox66 2001 225 2stroke. Motor start fine and idles fine but when in full throttle motor shuts off. This is any where above 4200 rpm. I have replace the fuel filter, added new oil and gas. Prior to this issue during normal opperation i was loosing 200-400 rpm after 30 minuites of opperation. Any ideas what the problem could be?

[boats.net]

Check compression, run fuel vacumn and fuel pressure test at wide open throttle.