During middle of take off run in a 737-200, the No 2 EPR went to 2.30 while No 1 EPR stayed steady at 2.15. Both N1 stayed steady at around 100%. F/O called "overboosting" and tried to drag No 2 thrust lever back from under my hand. Told him to set 100% N1 both engines and disregard EPR. He still tried to drag No 2 thrust lever back but as I had firm grip on thrust levers he didn't get far thank goodness. As OAT 30 C it wasn't Pt2 tube icing but later discovered blocked tube due insects and other sticky material.