Small Engines (Lawn Mowers, etc.): JD L118 Briggs #407777, operation speeds, work horse

Question
The flywheel on my mowers motor exploded while i was cutting the other day. I haven't opened it up yet. I would just like to know what could have caused this. The mower is only 2 years old and I am super easy on it. Also I am pretty mechanically savvy so how hard is it to repair myself?

Answer
The repair is relatively easy. It's a simple R&R procedure. The cause is a mystery. Occasionally a flywheel will be fractured during manufacturing. These flywheels usually blow in the first few hours of operation. The only other cause I know of is overspeeding the engine.
This is highly unlikely unless you have tampered with the governor linkage and controls.
When you say you are super easy on it what do you mean. If you mean mostly low operation speeds this could cause some overheating issues . This, might, cause the problem but I doubt it. This engine doesn't want to be babied. It is a work horse that wants to be driven hard every second it is running. It demands WFO all the time.

There is one more possible reason for the part failure. Parts break. It's that simple. If I could figure out why I'd be a millionaire.