How long do outboard motors last?

I have a 70hp Suzuki 4 stroke. I use it only on the weekends and i rinse it out with fresh water every sunday (before the week). It's a 2005 but it wasn't put into service until 2008 so it has 180 hours on it. Are these pretty much bulletproof given that you follow maintenance because occasionally I will run at full throttle for a few minutes(?).