It's a Kohler SV720 Courage engine and their filters are cheap.
Many makers ; check Ebay etc for prices/kits. $8 or so .........
What do you think of that engine ?
Like the koholer eng. Have it on several cub cadets, only had this model for less then year very little time on motor , thanks for tip totally for got it was a koholer motor , had kubota on my mine.