goplaneman,
Your's is definitely a lack of downthrust. Loosen the bottom bolts on the engine mount, then remove the top ones. Put at least two washers on the top bolts, BUT behind the engine mount, and re-install them. Then tighten the bottom bolts. (You'll have to remove the engine to do this.)

The right amount of downthrust will prevent the airplane from climbing at almost any motor speed, because the faster the prop turns the more "down" is created, so it offsets the wing (or horizontal stab) incidence.
Dennis-