3W 80 xi competition

[bornasp]

please i have one question...

i have 3w 80 xi

and have over 1 liter of oil thru it..and 15 litres of gasoline..

and when i am flyying i have a strange things hapening....when i am going down and the throotle stick is ad idle the engine starts reving up by it self and when i am coming on to landing it has a higher idle rpm ...but when it lands it is to fast but when i eventualy land it goes on normal rpm and goes off....and i didn not touch the throtle stick...

and when i get from full throtle to min throtle it goes off sometimes ( but not if i have trim high).. but i repeat when i fire it up on ground it is ok....i must trim it to high idle..and i cant fly with that..,i did not had problems like that with other engines..

what is the problem ???

help me please..(i know hot to tune the engine it is not my first..)

could it be a wrong adjusted sensor ??

[zoomer260]

I'm suprised that no one with this engine or similar problem has replied. Since I don't have one my suggestion is to look for air leaks on the intake side of things. When an intake is sucking air through any thing but the carb venturi high idle can result and it can come and go. Surging.

[Dan767]

I have this engine with very similar problems. First start fo the day, starts fine, idles fine. Go fly, idle is now higher than what it was when I took off. It will idle down after while, but in order to land, I've had to use the idle down function. When I taxi in, put the idle down switch back to normal and the engine is fine. I've fooled with the mixture and the carb. I believe there may be a reed issue, but I haven't looked inot that. It's been this way since new. Other than this, the engine is very strong and has been a great performer.