O.S. = "Oh Sh**" LA = "Lousy A**" engine! But in all seriousness, the real engines to avoid would definitely be the "Tower Hobby" .40's and the like... These are "Hit -or-miss" engines, the quality control is so low, that you never know if you're getting a good or bad one. I have two, "came with a whole bunch of stuff from a personal sale" One of them tower hobbies .40 works great, the other one just dies in th air, even after a great test run and warm up on the ground. I've broken a really rare on-of-a-kind plane because of it... I just cleaned out the carb, and seald the carb to the frame, and am going to try it again, but I don't know if it'll work... I hope so.

Live free or fly

Wings1150, Mike