Trying to see if anyone else has had this issue.

I have an 85 carrera that I went through the entire boat in 2017. I put new bearing s and rings in the motor and re built the pump at this time. I have been out every summer since then with no issues and the boat was always turn key and ran strong. last weekend I was running around 3/4 to wide open for around 30 seconds and? BANG. It made a crazy sound like the fly wheel fell off and was still running but no jet movement. I shut it down and parked it. So I started pulling it apart tonight and discovered that the end of the crank was broke on the fly wheel side. Didn?t spit any rods out or anything like that.

Does anyone know what would cause this?

Has anyone had this happen before?