John Deere GS30 Walk Behind Mower Engine

[JD3203]

Hi guys, I have a John Deere GS30 walk behind mower that I use every day in the spring and summer to cut lawns, last year a guy I let use it for a couple of days, blew the motor up! I have been looking every where for a new or used Kohler CV13 engine and cannot find one. Any ideas where i can find one before mowing season?? Any help is greatly appreciated! Thanks Mason