I run a 1988 Yamaha 150 HP Model P150TLRW on a Skeeter 185ZX. Up until this past season the engine has been starting when cold within a few seconds of turning the ignition key. This season it has become extremely tough to start. Once the engine starts for the day, it starts quick and runs great the rest of the time. I changed the spark plugs and installed a new battery. It turns over but seems to be flooded. This phenomenon began overnight. I have not had it professionally tuned up since it seems to run so good. The starting problem has me stumped. Any suggestions?