Why "uncertain"? Your .61 is twice the size of the recommended engine for beginners. There is nothing ambiguous about it...you have the wrong engine for this plane.

As to the elevator control, your second hand radio is probably a computer radio, and it may have been programmed by the previous owner. You need to use the manual and clear the memory for the model and get some help setting up your radio. It is very common to set it up for more rudder movement than elevator. Some coupling could be in there too.

As above, don't try to do this on your own.