Im posting this here as most of the OS140 users will be in this forum.
I have a brand new engine, which starts very easily, started first flick the first time I tried. I let it run at about 1/4 throttle for about 1.5/2 min the first time and shut it down. Now Im ready to go fly, I want to make sure I can get full throttle and an idle before flying.
This afternoon a mate and I tried unsuccesfully many times to get to full throttle. It starts very easily using the reverse flick method. At about half throttle maybe a tad more it dies. We tried, with the coarse taper needle set from 1 1/4 turns open to 2.5 turns open and each time the same result. We tried the finer taper needle at 1.5 to 2.5 turns open and same result. We then found some tiny pieces of plastic in the fuel filter, removed them and same result. Removed the fuel filter completely and same result. Tried lengthening the pipe set-up, same result.

My guess is its dieing because its too rich, some splatter of fuel from the carby when it runs and a fair bit of oil from the pipe outlet. I was reluctant to go leaner settings on the needle as I dont want to cook it being brand new. Having said that, there were some small bubbles evident in the line between the pump and carby (but no more than I see every time I fly my OS50SX) so maybe it is dieing lean. When it dies it does sag in RPM before it dies which makes me think rich rather than lean and the splatter from the carb makes me think rich.
This is my first OS140, but between my mate and I, we've succesfully ran engines from 46's through to Moki 180's and four strokes as well and never had so much touble getting full throttle out of an engine before.
Right now Im feeling like a dumb newbie who shouldnt be playing with big boys toys

Any ideas people ?