I have a 2006 15 hp kohler, used pretty good. Works excellent all day long, however every morning after not been started for 8 hours or so, it needs to be turned over for about 1 minute before it will start. Its getting worse as the summer goes on, could it be timing issue? I figure if it was a fuel issue it would happen all day but once its started once its good all day. Any ideas?? I changed the plug, air filter is clean, new gas every day, i'm going to add some fuel additive to see if it changes anything but help would be greatly appreciated!