i had to take the OS70 out because of broken sping valve . so today me and my friend assembled it back with new springs.
earlier i balanced the prop as well. i was flying with it till now not balanced.

well the engine wont idle on the ground over 30 seconds.... it dies . but this is not why i'm posting now.(could be the springs are too new and tight ? need to re adjust the valves ?)
the real annoying thing now is the noise the plane does. i heard that in the past at our field with the same plane and Saito82.
i hear the wing vibrate or harmonics/resonance into the wing/covering. very annoying.

very weird , i didn't do anything except new springs to both valves ,and balanced the prop. anyone know this problem ?

it's loader then the engine sometimes !