my morris has a tendency to climb all the way from 1/3 throttle up to full .
at lower throttle it seems it's making a something like a harrier. i thought it's an aft CG but rechecking and inverted flight shows that it is actually a bit forward.

what can cause this kind of behavior ?

you could check the incidence on the wing and tail or the angle of the incidence on the engine

It sounds like you have positive incidence. You can raise both ailerons.

Sometimes when you set the aileron trims at the ground inverted, the weight of the aileron surface may bring them toward the canopy; whereas if you set them up right, its weight will bring it toward belly. Try to set the aileron trim so when upright the ailerons will line up with wing's incidence line.

Fly the plane about 1/3 to 1/2 throttle straight and level and take the throttle to idle and watch to see how the plane reacts. If the planes dives you have too much up thrust. I would suspect you have a little too much up thrust.

Check CG with the wing on the plane.
Move CG forward just a little at a time.
Check elevator trim, neutral.

Ditto Bobby Richardsons post, except I'd recommend a higher throttle setting. I'd suspect your going to see the plane balloon when you chop the power (too much down thrust). You can check your incidence by getting it trimmed for S&L then take it up high slow it to stall and then point it straight down should come straight down hands off if it's right.

Mike

Are you holding up elevator when you get the harrier condition ?

If you are, then i think you maybe a little nose heavy.
If you are not, then you maybe a little tail heavy.

From your discription though I would say you are a little nose heavy and need to use a little more throttle management for your landings.

Lou

thanks guys i will test your suggestions on my next flight.

p.s

the plane harriers even below third throttle hands free.