I'm not impressed with the Evolution 46 at all. We tried for over an hour yesterday to set the high speed needle valve with no luck. Basically you could get the engine to run rich, then just sitting there at WOT it would go leaner and leaner till it died (or you closed the barrel just before it did. No air bubbles, hot plug, fuel line, tank and fuel good. Most likely an air leak somewhere that results in this behavior. I've been running glow engines for over 30 years and this is the first one where the high speed end couldn't be set. Maybe Horizon can correct the problem but I'd rather just get an OS 46AX.

Another student had a 60 size evolution in his plane that did run OK except that the low speed needle valve needed to be closed far lower than the installed stop allowed. Once that was defeated, the engine transistioned nicely and ran strong. Sealing an engine properly should be a no brainer but obviously the Chinese manufacturers don't really understand quality control. I've had other brands of Chinese made engine that almost always have air leaks when there is a problem.