I am having issues with my Legend V-1000. Before the engine gets to operating temperature it runs perfect. I can run it full out. One it is warmed up and I try to push it past 5000 RPM it begings to sputter and bog. When it gets back down to 5000 RPM or below it is fine. It will occasionally let me exceed 5000 RPM if I take it up slowly. It has a new fuel pump and new plugs. Is this a fuel issue or electrical? Any suggestions are appreciated.