ORIGINAL: insalacosm
I've been having the same problem with my YS 110S. It runs great in flight, idles fine while in flight, but for some reason it always dies on final approach eventhough I don't touch the idle trim. I'm running CoolPower 30% Heli fuel and a 15x8 prop.
Steve
This is one of the first symptoms I started having. I found that the engine didn't always back down to the same idle point. I'd set my trim to idle at 1900, sometimes it would only drop down to 2300. If the engine doesn't drop all the way down to it's lowest point and I set my trim, then it would drop below 1900 when it finally did (on approach, several times). Hope this makes sense. I had to send mine in to YS Parts and Service as it ended up overheating all the time. They have it but haven't started on it yet. I'll post anything I hear if it's at all related.
People seem to think my problems were related to over-propping the engine. What prop and fuel are you using?