Has anyone had any luck flying these engines. Ive heard good and bad, please give some input if you have some

If you're talking about MVVS engines from the Czech Republic, I've had GREAT luck with 'em. Own 4 in total (the only other manufacturer from whom I own more engines is Thunder Tiger), one 40, two 49s, and one 91. The 40 with an 11x4 prop gives a 5lb profile plane unlimited vertical. The 49s is more powerful than the Asian 46s out there, and the 91 is literally a stump puller. Most of the issues that people post are in regards to the carb settings. But I've found once broken in (takes about 1/4-1/2 gallon using FAI, you can run 10-15% after running in) and tuned, they are as reliable as anything else I own... My current arsenal includes TT, OS, YS, Rossi, Webra, and MVVS glow engines.

Thanks alot racer