well I Just killed my u can do 3d 60

I was hovering low when the engine decided to die and I had no way of recovering, it juts broke in half

oh the engine was Saito 125 with iron bay regulator (tank is at the CG) I have been flying with 16x4 for a month or so, and decided to try 16x6 and I did richened things up a bit since the 16x6 puts more load on the engine but after finishing more than half of the tank, while I was hovering, the engine just lost rpm and died. will overheating cause the engine to die like that? I mean if it was lean or rich it would have died from the begining right, I mean why would it fly and hover nicely for almost 10 mins or so, and all of the sudden she dies while hovering.
any thoughts?