I have a vanguard V21 engine in a lawn tractor and can't get the rpms up. The throttle is wide open but rpms are low. The choke is off. Its only 1 yr old with few hrs on it. Any ideas??

How are you checking RPM? The engine sounds like it is idling? If so maybe you are not using controls properly. If confident that you are checking RPM and using controls properly you have a major engine problem that will require more info or shop diagnostics.
Don