Stepper motors are rated in terms of maximum average current per winding, so a 1.7 amp motor can at most be run at 3.4 amps (both windings) in full step mode. Any more current and the motor will overheat. They can run hot, sometimes too hot to touch.
The product data sheets for the L298 motor driver chip are "overly optimistic" (to be generous) in quoting 2 amps total per motor or winding. They overheat when more than about 1 amp is drawn, as documented by these guys The Motor Driver Myth — Rugged CircuitsRugged Industrial Arduino Microcontrollers and by hundreds if not thousands of posts on the Arduino and other forums.