sabre ohv B & G 15.5 -help

[dwilken5]

folks- i have a 15.5 hp B & G ohv 28N707 engine on my sabre. it started very hard so i adjusted that valves as per instructions. to .oo4. that didn't help, so i pulled head and replaced gasket. checked valves again and buttoned up. it started once, and hasn't started since. the old gasket i took out didn't look bad to me. when i pulled the ohv cover plate off to check the valve setting again there was a little oil in there. not much, but it was there. changed plug, checked spark but still no start. one back fire and that's it. any suggestions. i'm lost & flustered. dave in ohio