I have an ST G-51 on a Phoenix Sea Bee. I'm not a big fan of this engine, but I don't have big enough issues to replace it either. It idles rough but runs well WOT. This could be attributed to either tuning and/or break-in, but I will say that this engine has allowed me to improve my dead-stick landing technique on low-wing pattern ships. [:@]

I love my OS engines.