Kohler CV22S white smoke

Kohler CV22S spec 75534 Craftsman 917.273080 Brief history. Owner was unable to start mower, had inlaw tell her it was beyond repair. Battery removed and mower set inside storage building for several months before I looked at it. Battery cables covered with rust, cleaned them, connected battery charger-starter and mower started with little trouble, but blew white smoke from exhaust, and observable evidence of oil leak from around exhaust connection to block. Ran fine with no load but continued to blow white smoke for several minutes before I shut it off and loaded onto my trailer. Muffler and exhaust appears to have been replaced or repaired with a rigged replacement, including coat hanger. I personally used the mower for her, last season and it was running fine with no smoke while I used it then.