Troy-Bilt Rototiller problem - won't rev up?

Take off the air filter or hose attachment so you can see the carb when you crank the engine. Slowly increase the throttle to see if the throttle cable is slipping. Also look at the choke erfly to see if it is closing and killing the engine. If all is good, then it sounds like maybe a needle valve may be dirty or a jet is clogged. If the engine runs good at idle the problem is minor and it's probably just a small adjustment. You said you cleaned the carb but did you completely take it apart? I suspect something loose first and then something dirty. Good luck.