2-Stroke Engine Selection
Stick with the .61FX in lieu of the .91FX. True, the .91 is the same physical size and weight of the .61, but it will burn more fuel and tends to overheat from a lean setting quite easily. I have an OS .61FX on a 1/4 scale Spacewalker that weighs 8 1/2 lbs. and I don't see where it's a weak engine at all.