Programming contant power to lift(easyC)

I have a six-bar lift that does not have trouble going up on two motors at a 7:1 ratio, but even with rubber bands, it sinks down about an inch when I raise it to the highest position.
To solve this I want to program the arm motors in operator control to constantly be powered at motor value 10, so that the arm stays up. I do not know how, so can anyone help me out please? Thanks.