Arduino Mega enable pin connected to timers

Other Hardware 3rd Party Boards
3

Why not pinMode(4, OUTPUT);

Why would you expect an output signal on an input pin?

If you want to use timer in the main code,
it has to be volatile and accessed with disabled interrupts.

No need to enable something that is enabled by default and was never disabled.

BTW.

Timer0:
 Timer0 is a 8bit timer.
 In the Arduino world Timer0 is been used for the timer functions,
 like delay(), millis() and micros(). If you change Timer0 registers,
 this may influence the Arduino timer function.
 So you should know what you are doing.