Thanks for replying datzenmike,
once it get closer to 60mph it would hesitate and refuse to go faster when the gas pedal is fully press down. doesn't run rough or misfire at all.
just now it happen again at 40mph. would hesitate and would go! it would lose power for a lil bit then will run fine. I haven't had a chance to look at the carb yet. since it's raining and i live in apt that doesn't have garage.