Got a older exmark hydro viking with kaw fc420v. Read a lot of stuff on here and have some questions. It tries to start, fires for a few seconds then puffs white smoke like its flooded. I took the carb off and cleaned it really well, but still same thing. People have said it could be valve issue or seals on the float valve seal letting too much gas into the bowl. What do you guys think? I found the manual on here and feel confident in being able to adjust valve clearance.