Doug,

Not sure either, only time I had an engine run without the HS needle in was a 2 stroker Tower 46, the LS needle was cranked all the way in, I adjusted it per the book and it ran great. Are the old Saitos AAC's or ABC's?

I know I was ready to rip the 72 out of my UCD 46 until I tried 30% ( I use Wildcat Youngblood), nite and day difference.

Another item, and this comes from a respected heli pliot at our field, he says any nitro over 18% is really just adding cooling capacity.....not power.

My hi temp problems I found were to my over proping the engine before I knew better.

Mac