Have a 2015 CC with a courage 23 Kohler twin and since new I've never had a single issue with it till now. Went to mow for the 2nd time this year and motor is hunting/ surging. I did do my due dilagents and completely serviced the machine. So did some reading and replaced everything that's has to do with fuel. New filter fresh fuel new fuel pump new lines new carb now I can get it to idle but when I throttle it up same thing. So I thinking vacume leak, did all the std checks with water bottle , nothing took an inspection motor to look at bottom side of head and lot of carbon tracing around exhaust port on #2 cylinder so now I'm doing head gaskets ,oh wait top end kit from Kohler is no longer available. So one any idea where to get correct parts and two possible that I'm chasing my tail. Thoughts?