I agree with the wing incidence check, positive will make you climb under power, also, not enough negative incidence in the tail will do the same.

Average light plane:
Main wing: positive 1'
Tail: negative 3'
Engine: down 2'
Engine: right 3'

I have a hangar 9 Easy Fly that I bought for my wife and it came with about 6' of downthrust in the engine and It wanted to climb alot under power, so I reduced the downthrust to about 2' and it now flies the way I like it.
this is why I say reduce the downthrust, if it is high to start with...