Not sure which brand you have, and I don't think you can change the blower, but a good cleaning may help. If your unit drops it's output directly down to the coach, you need to take off the bottom grill. THere will be 4 large, long screws in the corners of the duct that are holding the unit on the roof. Pull them, go on the roof and you can work the unit up. You'll need to remove fiberglass cover, power cords, thermostat and perhaps a few other wires and/or lines. For example, my Tiffin has a condensate drain line through the roof to the front and rear caps.
If your air dumps into a roof duct setup, you need to go on the roof, pull the fiberglass cover and get at the 4 screws that way. 2 are easily seen, but on mine, 2 are behind a piece of galvanized metal that needs to be bent up to get to them. It's sealed with sealer and/or foam (tape). You should also be able to see the fan from the top.