I have 2 SK 90 engines, and both run fantastic. I did have one snap a crank, but warranty service repaired it, and it is running just fine. I have yet to have a deadstick with either engine, except for the one time when the crank went. I would not hesitate to buy another one. Good power, good value, and pretty darn good warranty service. Oh...one more thing. I did have a little trouble with one of the engines throttle barrel sticking, but after taking a little emory cloth to it, it seems to be working fine now. I currently have one SK 90 mounted on a Hog Bipe, and the other mounted on my Super Sportster 90/120. Both engines pull both planes around pretty good, and both are propped with 14X6 Zinger props. I may try an APC 15x6 on one of them just to see how it likes it.