my two cents....

inverted, 2 cycle engine idle issue solved

I got my UCD 46 for x-mas and it now has about 15 flights on it. I have an OS 61FX on it. i had a heck of a lot of trouble getting the engine to idle for more than 7 or 8 seconds initially with the OS #8 plug. I ended up changing the plug for a Fox R/C Long with idle bar. Idled and ran much better. Continued to adjust the low speed needle to the lean side. Factory setting is 1/2 turn out with carb closed. I ended up at about 1/4 turn. High speed needle is also a bit on the lean side. Motor still runs a very tiny bit rich, fuel leaks etc. (because of the fuel tank location), but motor runs and idles wonderfully! This past weekend I removed the baffle in the muffler before going out to fly hoping that the pressure to the fuel tank would be reduced slightly. Don't know if the pressure has been reduced but the engine is running better than ever. I can idle it for extended periods of 3 or 4 minutes and it wont die on me.

If this where to have been a kit I would have slightly rotated the engien so the plug isn't pointing directly down, but to do that on this arf it would have required some surgery I didn't want ot do.

So, Fox R/C Long plug with idle bar, baffle removed from muffler, and slightly lean needle settings....did the trick!
Oh, running 13x4w prop.

Can't leave without mentioning that this plane is awsome! The 61FX will hover the plane but with almost full throttle. There is just a little bit of power left to pull it out.