I have an 05 250 TB that bogs down when I give it throttle. Its got good spark, battery, and new plug. It sounds like when you gas it without mashing the reverse overide buttun. Oh yeah, does anybody know how to disable that sucker?
The carb seems to be in proper adjusment. Maybe no timimg advance?

 

unhook the black wire on the rev limiter box. if you take the hood plastic off its right there. check your spark plug to get a read on it. sometimes running it lean will cause it to bog. if it is lean and the carb is in adjustment try spraying carb cleaner around all gasket areas. might have an air leak somewhere. 2cycle motors need to be sealed up pretty good.