This engine problem is a new one on me.
Magnum 61 2 stroke. Runs fine on the ground. Runs fine being held nose-up. Transitions well from idle to full throttle. It stumbles and sometimes dies coming back from full throttle to idle. If you ease it down in 2 seconds you're fine, chop it and it's dead.
Dies shortly after lifting off the ground if done at full throttle. Can get up in the air and fly at half throttle.
Now the even stranger part, the engine won't turn off in the air. I tried to kill it coming in on a landing and it kept going. I considered that maybe the air was spinning the prop and thus the engine (12x6 prop). Really really doubted it, even my 46 with a 12x4 doesn't do that, but it crossed my mind. After it starts to roll out I give it gas and it comes back to life.
I was suspecting maybe an air leak but I can't find it. Might put a new o-ring around the carb if I can track one down. Could it be leaking around the high speed needle??
There is a wide range of adjustment on the high speed, it doesn't seem to ever go to the "rich 4 stroke" that I'm used to for break-in, but when it gets lean it gets lean fast and dies (has the remote needle, those are nice for adjusting but I have to constantly remind myself to wait for the adjustment to "catch up" to the carb from the needle). Since it idles fine I haven't messed with the low speed needle (and it's a real pain to get to).
The engine was used on a used plane I bought. I don't know much of the history of it but the guy was an acrobatic flier and had some health problems and had to give up the spot.
I am open to any suggestions....
Thanks, Steve