hy guys i bought the edge 540 47" v3 from OMP with a OS 81 FS

i flew it today but i dont like the way that the plane flews :S:S i dont know if i setup it wrong or waht happen because when i slow down de engine, the plane goes down very fast like if the nose was too heavy.

Then i added weight in the tail, now the plane gets up and when i flew it inverted it gets up again, but when i slow down the engine it goes down like if the nose was heavy again...

i dont know if the engine have a wrong angle because i make biger the hold of it.
how can i know if is correct the angle of the engine

Can anyone help me???