This is a picture of a 914 during a test run by Rotax. I got this at a maintenance class I took in Canada. Seems they wanted to see just how long and hot they could run it. Can’t recall time but I think it was 24 hours or more and the engine came out remarkably well.
Nice to know you can run them a little hot and they will survive, can’t say what the rest of the stuff under a cowling might look like!
Jerry"