By the outside air, I assume you are referencing the hot air being exhausted from the unit on top and not inside of your RV. This air is supposed to be hot because it is coming through the condenser and evaporator coils to remove the heat from the inside air.
If the coils are dirty and clogged, it makes it difficult, if not impossible, for the heat removal process to work well. If the coils are clean you are experiencing an overload because of a faulty fan motor or compressor.
The following article will go into more detail about the coil cleaning process. Good luck on your maintenance!