Check the throttle linkages to make sure they move freely. You might want to install the throttle mod to make it work smoother. If you look for my posts you will see some pictures I posted a while back. If you cant find them Ill post them again.
If the engine hasnt run in a long time there could be residue build up in the carb intakes. You can use an air compressor to blow it clear.
Nitro fuel naturally attracts water so if it wasnt sealed tight it could have gone bad.
If you can, take some pictures of the throttle set up. Maybe we can see if something is wrong.