Hi, i am a auto tech that has a friends honda gcv190 that quit running,the carb was gummed so i cleaned with amsoil powerfoam, however after pulling forever and getting it to run 1-2 times it pops slightly out the intake and quits, i have checked cam timing ,belt driven, flywheel key etc. i loosened the valves to see if i could get the intake to seal with no luck, i am suspecting that it got dosed with two stroke fuel as the owner stated it was smoking a bit, the blade shows sign of impact, and the valve cover had its seal broke by yard debris...but this has be stumped, with no vacuum port to see what is going on once it does start i'm getting frustrated. i suspect that the intial start is when the valve lift is low however when rpm hits it flings the valve open and is sticking intermittent at higher lifts. i have had the cover off a dozen or so times a operated the valves by hand and can't feel it sticking...thanks.