Helped a guy with a Evolution 46 today that had the same problem. I finally put an idle bar plug in it that I had, and I was able to get it to idle nice at 1800 rpm and it ran great. Maybe thats what the ST needs. I told my bud about that, so maybe he will try it. I think he has the Giles sold to anopther guy already, so he can try that if he wants. I flew my cessna 182 with the Saito 56 maybe 5 times today, and didn't use a whole tank of fuel. Thats the way I like em to run. lol