I find the interactive drawings much nicer to use and knowing how Winnebago does keep things year to year, I went to the 2011 model to look at this drain. Does this look the same for your 2009, etc.?
Click to get better view.
Seems to be very short run on a small tube. We clean this sort of things with air when they stop up. Any chance you can hold a small tube over the hole and simply blow into it hard enough to clear debris? Or would it need a compressor?
One problem with tubes that are getting older and tend to get brittle is that we can push a wire through the tubing side and then we DO have a big problem as we have to get the equipment apart to replace the tube!
Alternate thought to try to avoid shooting our foot?
Why no RV year, make and floorplan on MY signature as we suggest for others?
I currently DO NOT have one!