I have a Webra 20 heli engine (using it in a plane), that starts first time and idles fairly well (need to finish tuning low speed idle), mid to upper mid throttle is ok. But jam the throttle to full and it flames out. Is this usually a "too lean" high speed needle setting condition?




Thanks.

low speed setting afects the high speed setting. i always tune the low end first then the high end, then sometimes you have to tweak the low end to get the transition good!


john

Yes, it sounds like a too lean condition. I always set high speed first, then dial in low speed mixture (like the instructions will advise). Low speed will affect the high speed setting as stated above, but chances are you will have a hard time setting the carb if you don't set high speed first. Richen up your high speed needle from where you are set now (half to 3/4 turn or so) just to get it a little fat. At full speed, lean out your high speed to attain top rpm, then richen it back up a couple clicks. Now try your transition from idle to full speed. If it still flames out, richen your low speed mixture (or if it's an air bleed carb, turn counter-clockwise to reduce the amount of air in order to richen). If it stumbles and blows smoke, it is too rich.
Hope that helps.

Pilgrim

OK thanks guys. I think I will try going a bit more rich on the high speed side then richen up the idle speed a little also.

See what happens.

Just to let you know....Looks like the problem was the high speed needle was to lean. I richened it up until I got consistent full throttle with the nose of the airplane pointing up. That setting made the low speed needle too rich, making acceleration from mid throttle to full throttle sluggish. I leaned out the low speed needle a bit which helped with the transition from mid to full throttle. I also had to richen out the high speed a bit also after leaning out the low speed needle. Seems to run fairly well now. Once again thanks guys.

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I'm not sure what you mean proteus.