Is the blower changing speed or just the volume, if volume maybe a mouse nest or wasp nest. Leaves?
I had a very industrious mouse move all of my rat poison from the top of my cabinet to inside the breather on my Grizzly 700, he ran out if mojo at some point, but still had the entire bottom covered in green pellets, took me 30 seconds on staring in preponderance to figure out what was in my breather box. Then minutes to marvel at the efforts.
I have not looked at this, but maybe consider sticking a shop vac up to it and see what you can get out?
2004 Rubicon N th Degree complete set, 4.5” with long arm, Stinger, plus all plates minus front diff, Tom Woods driveshaft front/back, 305/70/16 tires Cooper STT Pro, weight 4400lbs, New owner 6/12/19