2001 8hp 4 stroke Yamaha stalls out and won't restart

I bought a 2001 motor in August of 2008. It ran great until September of 2009. Since then, it has been to the shop repeatedly (a Honda dealer) I use it as an escort boat on long lake swims (90 minutes and longer). It runs at idle, but I always warm it up and "cool" it down at higher speeds prior and subsequent to my swims. It stalls out and will not restart. The carburater has been rebuilt twice, replace the fuel filter, pump, gas line and tank. I just got it back 3 days ago. It worked the first two, flawlessly, but died 10 minutes after starting my swim yesterday. Yesterday, I noticed gasoline in the water and some smoking upon startup. It ran a bit rough and then died. I am thinking of getting rid of it unless you guys can help me out. Thank you.