define output as int variable

According the kind to define the output ( directly or using a int varaible), the voltage is not the same

Example:
Work correctly

void setup() {

pinMode(13, OUTPUT);
}

void loop() {
digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}

Do not work correctly: pin 13 = 1.6vmax and the led doaes not light

int _ABVAR_1_pin13 = 0 ;

void setup()
{
pinMode( _ABVAR_1_pin13 , OUTPUT);
}

void loop()
{
_ABVAR_1_pin13 = 13 ;
while (1)
{
digitalWrite(_ABVAR_1_pin13 , HIGH);
delay( 1000 );
digitalWrite(_ABVAR_1_pin13 , LOW);
delay( 1000 );
}

}

any idea where the probleme is ???