Originally Posted by DJ_Shakespear

Question 1: What engine and fuel are you using?
Question 2: 200 what? Celsius or Fahrenheit? I hope its Fahrenheit!

That sounds like one hell of an engine!

Doesn't sound like you are doing anything wrong, but possibly letting it run only when its around 200 is not letting the piston and sleeve wear themselves in together like it would when its colder because of expansion?