Hi Wounded, I have the same plane with an OS 91 four stroke with pump. I built it in 2000. It is a great flying airplane and have never had a problem except for a lost muffler once. It is the first plane I use at the beginning of a flying season and any time I am rusty as it is a very forgiving airplane. With the 91 the plane can be slowed to a crawl for real pretty landings. I wouldn't trade mine for anything. (well almost anything). It does pitch a little to the belly in knife edge but that is easily mixed out with your radio.