Oh my gosh, I wish I had seen this earlier. I bought a brand new R66 two years ago with the heavy duty battery. I was taught to inject fuel at between 12 and 15. I got a hot start and at annual was informed it would cost me 75k to R and R the engine and have it fixed. Over six months later I got my helicopter back. I had my BFR and got extra special attention on starting and preventing and preventing hot starts I also bought a heavy duty external power pack so I had no trouble spinning well past 15% before introducing power.
I always double check throttle closed and fuel pulled completely off before starting. The other day I had to fly 10 miles to have an AD tended to and I noticed the EMU flashing again. When I had the service center check it he reported back that Rolls Royce analyzed the computer report and I had a hot start and it would require close to 100k to fix it this time. I honestly don't know what could have caused the hot start and the mechanic told me there was no sigh exterially that there had been excessive heat. I can't seem to get any response from Robinson or Rolls Royce as to what may be the issue other than pilot error. There is either a flaw in the system or the helicopter needs some auto overheat safety switch. How many out there have had this problem and been left holding the bag like myself?