I have a SRM-225 and I have recently noticed when I have it at full WOT it doesn't seem to be as high as it was when I purchased it last year. Idle is fine. Any idea where the high idle screw is? This is what I have always done to set the high... While running at WOT, adjust the high screw to richen up the mixture. Turning CCW richens the mixture and CW will lean the mixture. Explore the adjustment range and find the "sweet spot" setting where it runs good and pefectly smooth at full RPM at WOT. Richen the mixture about 1/8th of a turn from this sweet spot setting to set the mixture slightly on the rich side.