The airflow path on an Efco is not obvious at first glance.
Air enters through the starter housing (similar to a Husky, I think -- never having owned a Husky ), travels through the carb area, and upward through the filter. The filtered air makes a 180 turn into the carb boot.
The green arrows show the path.
Hope it makes better sense now.
Took a look at my 5720 Cub Cadet (Efco ), has the same filter as yours and the same amount of fine dust. If you had taken the picture from the other side I might not been so confused. Looks like it leaks where the filter sits in the cover, not a good design. Might need some silcone where the filter meets the cover. Steve