Just got finished spending the last day and a half cleaning out my carb because of a crappy fuel filter. Took it out for a spin on friday, hit 2nd, about to hit third and then a sudden loss of power. Felt like I was running at 80% and it would barely idle. Got it home thinking i had a vacuum leak, sprayed down the manifold and carb, nothing. Tight as a fish's backside. Then I noticed as a moved the idle adj screw, nothing happened. Darn primary and idle circuit clogged. Pulled the carb, opened the topand noticed rust in the bottom of the carb.I was running a fuel filter, but it was one of those cheap units. Not any more. This goes to prove you need to run a good fuel filter! What amazed me the most. . . the symptoms was almost identical to a vacuum leak.